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@ARTICLE{FangXDJ03,
	author	    = {Fang, A. P. and Xu, H. L. and Dai, Z. W. and Jiang, Z.
	  K.},
	title	    = {Theoretical study of electromagnetically induced
	  transparency in Er3+: YAlO3 crystal},
	journal     = {Physica B},
	year	    = {2003},
	volume	    = {328},
	pages	    = {204-210},
	abstract    = {By using the density matrix theory of interaction
	  between light and matter, and relevant parameter calculations of
	  the relaxation rate, the dipole matrix elements and the ion density
	  for a three-level ladder model, we have discussed theoretically the
	  possibility to realize electromagnetically induced transparency
	  (EIT) in Er3+:YA1O(3) crystal. (C) 2002 Elsevier Science B.V. All
	  rights reserved.
	  }
}

@ARTICLE{Xiao03,
	author	    = {Xiao, M.},
	title	    = {Novel linear and nonlinear optical properties of
	  electromagnetically induced transparency systems},
	journal     = {IEEE J. Sel. Top. Quantum Electron.},
	year	    = {2003},
	volume	    = {9},
	pages	    = {86-92},
	abstract    = {We describe some interesting linear and nonlinear
	  optical properties of three-level electromagnetically induced
	  transparency (EIT) systems, such as absorption reduction, sharp
	  dispersion change, and enhanced Kerr nonlinearity. These novel
	  optical properties are very useful in enhancing efficient nonlinear
	  optical processes, which can find applications in optoelectronic
	  devices. We present some experiments done in our group in the past
	  few years with three-level atomic systems, especially more recent
	  experiments with EIT medium inside an optical cavity.
	  }
}

@ARTICLE{WuWZ03,
	author	    = {Wu, Y. and Wen, L. L. and Zhu, Y. F.},
	title	    = {Efficient hyper-Raman scattering in resonant coherent
	  media},
	journal     = {Opt. Lett.},
	year	    = {2003},
	volume	    = {28},
	pages	    = {631-633},
	abstract    = {We propose and analyze a hyper-Raman scheme for
	  generation of coherent light in a five-level atomic system based on
	  electromagnetically induced transparency (EIT). We show that EIT
	  suppresses linear and nonlinear photon absorption and enables the
	  hyper-Raman process to proceed through real, nearresonant
	  intermediate states. The scheme greatly enhances hyper-Raman
	  efficiency and may be used for generating short- wavelength
	  radiation at low pump intensities. (C) 2003 Optical Society of
	  America.
	  }
}

@ARTICLE{LiS03,
	author	    = {Li, Y. F. and Sun, J. F.},
	title	    = {Ultra-narrow electromagnetically induced transparency
	  and inversionless gain in a ladder-four-level system},
	journal     = {Acta Phys. Sin.},
	year	    = {2003},
	volume	    = {52},
	pages	    = {547-555},
	abstract    = {In this paper, we study the effects of Rabi
	  frequencies and multi-path radiation on the electromagnetically
	  induced transparency (EIT) and the inversionless gain in a ladder-
	  four-level system driven by two-coherent fields. The Rabi
	  frequencies of the field-driven transition from the upper level to
	  middle levels play an important role for the realization of the
	  ultra-narrow EIT and inversionless gain. Different excitation
	  mechanism can change the position of the EIT. The action of the
	  spontaneous alignment of the dipole moment is investigated. The
	  explanation for the numerical results is presented using the theory
	  of dressed state.
	  }
}

@ARTICLE{PaternostroKH03,
	author	    = {Paternostro, M. and Kim, M. S. and Ham, B. S.},
	title	    = {Generation of entangled coherent states via
	  cross-phasemodulation in a double electromagnetically induced
	  transparency regime},
	journal     = {Phys. Rev. A},
	year	    = {2003},
	volume	    = {67},
	pages	    = {023811},
	abstract    = {The generation of an entangled coherent state is one
	  of the most important ingredients of quantum information processing
	  using coherent states. Recently, numerous schemes to achieve this
	  task have been proposed. In order to generate travellingwave
	  entangled coherent states, cross-phase-modulation, optimized by
	  optical Kerr effect enhancement in a dense medium in an
	  electromagnetically induced transparency (EIT) regime, seems to be
	  very promising. In this scenario, we propose a fully quantized
	  model of a double-EIT scheme recently proposed [D. Petrosyan and G.
	  Kurizki, Phys. Rev. A 65, 33 833 (2002)]: the quantization step is
	  performed adopting a fully Hamiltonian approach. This allows us to
	  write effective equations of motion for two interacting quantum
	  fields of light that show how the dynamics of one field depends on
	  the photon-number operator of the other. The preparation of a
	  Schrodinger cat state, which is a superposition of two distinct
	  coherent states, is briefly exposed. This is based on nonlinear
	  interaction via double EIT of two light fields (initially prepared
	  in coherent states) and on a detection step performed using a 50:50
	  beam splitter and two photodetectors. In order to show the
	  entanglement of an entangled coherent state, we suggest to measure
	  the joint quadrature variance of the field. We show that the
	  entangled coherent states satisfy the sufficient condition for
	  entanglement based on quadrature variance measurement. We also show
	  how robust our scheme is against a low detection efficiency of
	  homodyne detectors.
	  }
}

@ARTICLE{AgarwalD03,
	author	    = {Agarwal, G. S. and Dasgupta, S.},
	title	    = {Laser-induced breakdown of the magnetic-field-reversal
	  symmetry in the propagation of unpolarized light},
	journal     = {Phys. Rev. A},
	year	    = {2003},
	volume	    = {67},
	pages	    = {023814},
	abstract    = {We show how a medium, under the influence of a
	  coherent control field that is resonant or close to resonance to an
	  appropriate atomic transition, can lead to very strong asymmetries
	  in the propagation of unpolarized light when the direction of the
	  magnetic field is reversed. We show how electromagnetically induced
	  transparency (EIT) can be used in atomic vapor to mimic this
	  magnetochiral effect that occurs in natural systems. EIT can
	  produce much larger asymmetry than the well-known magnetochiral
	  effect as we use the dipole-allowed transitions here. Using
	  density-matrix calculations we present results for the breakdown of
	  the magnetic-field-reversal symmetry for two different atomic
	  configurations.
	  }
}

@ARTICLE{GreentreeRVDdSM03,
	author	    = {Greentree, A. D. and Richards, D. and Vaccaro, J. A.
	  and Durrant, A. V. and de Echaniz, S. R. and Segal, D. M. and
	  Marangos, J. P.},
	title	    = {Intensity-dependent dispersion under conditions of
	  electromagnetically induced transparency in coherently prepared
	  multistate atoms},
	journal     = {Phys. Rev. A},
	year	    = {2003},
	volume	    = {67},
	pages	    = {023818},
	abstract    = {Interest in lossless nonlinearities has focussed on
	  the dispersive properties of Lambda systems under conditions of
	  electromagnetically induced transparency (EIT). We generalize the
	  Lambda system by introducing further degenerate states to realize a
	  "chain Lambda" atom where multiple coupling of the probe field
	  significantly enhances the intensity-dependent dispersion without
	  compromising the EIT condition.
	  }
}

@ARTICLE{ZhuL02,
	author	    = {Zhu, K. D. and Li, W. S.},
	title	    = {Electromagnetically induced transparency mediated by
	  phonons in strongly coupled exciton-phonon systems},
	journal     = {Appl. Phys. B-Lasers Opt.},
	year	    = {2002},
	volume	    = {75},
	pages	    = {861-864},
	abstract    = {It is shown theoretically that electromagnetically
	  induced transparency (EIT), due to strong exciton-phonon coupling
	  can occur in strongly coupled exciton-phonon systems such as
	  polymers and organic semiconductors and lead to ultra-slow light
	  effects. The results indicate that the strong coupling of excitons
	  and phonons is important, but the excitonexciton interaction
	  plays a small role in the generation of the EIT. Numerical results
	  for polydiacetylene-toluene sulfonate are also presented. This EIT
	  in a solid-state medium might be utilized for efficient multiwave
	  mixing and quantum nondemolition measurements, as well as for novel
	  acousto- optical devices.
	  }
}

@ARTICLE{ZhangJSDW03,
	author	    = {Zhang, Y. L. and Jiang, L. and Sun, Z. R. and Ding, L.
	  E. and Wang, Z. G.},
	title	    = {Effect of four-wave mixing on electromagnetically
	  induced transparency in Lambda-type system with a two-photon probe
	  field},
	journal     = {Chin. Phys.},
	year	    = {2003},
	volume	    = {12},
	pages	    = {174-177},
	abstract    = {Using density matrix equation, we calculate
	  analytically as well as numerically the effect of the four-wave
	  mixing (FWM) field on electromagnetically induced transparency
	  (EIT) in the rubidium 5S(1/2)-5P(3/2)-5D(5/2) Lambda-type system
	  with a twophoton probe field. The calculated results are in good
	  agreement with Fulton's experimental results in 1995.}
}

@ARTICLE{ValenteFL03,
	author	    = {Valente, P. and Failache, H. and Lezama, A.},
	title	    = {Temporal buildup of electromagnetically induced
	  transparency and absorption resonances in degenerate two-level
	  transitions},
	journal     = {Phys. Rev. A},
	year	    = {2003},
	volume	    = {67},
	pages	    = {013806},
	abstract    = {The temporal evolution of electromagnetically induced
	  transparency (EIT) and absorption (EIA) coherence resonances in
	  pump-probe spectroscopy of degenerate two-level atomic transition
	  is studied for light intensities below saturation. Analytical
	  expressions for the transient absorption spectra are given for
	  simple model systems and a model for the calculation of the
	  time-dependent response of realistic atomic transitions, where the
	  Zeeman degeneracy is fully accounted for, is presented. EIT and EIA
	  resonances have a similar (opposite sign) time-dependent line
	  shape, however, the EIA evolution is slower and thus narrower lines
	  are observed for long interaction time. Qualitative agreement with
	  the theoretical predictions is obtained for the transient probe
	  absorption on the Rb-85 D-2 line in an atomic beam experiment.
	  }
}

@ARTICLE{WuSZ03,
	author	    = {Wu, Y. and Saldana, J. and Zhu, Y. F.},
	title	    = {Large enhancement of four-wave mixing by suppression
	  of photon absorption from electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2003},
	volume	    = {67},
	pages	    = {013811},
	abstract    = {We analyze a four-wave-mixing (FWM) scheme in a
	  five-level atomic system based on electromagnetically induced
	  transparency (EIT). We show that EIT suppresses both two-photon and
	  threephoton absorptions in the FWM scheme and enables the
	  four-wave mixing to proceed through real, resonant intermediate
	  states without absorption loss. The scheme results in a several
	  orders of magnitude increase in the FWM efficiency in comparison
	  with a recent scheme [Phys. Rev. Lett. 88, 143902 (2002)] and may
	  be used for generating short-wavelength radiation at low pump
	  intensities.
	  }
}

@ARTICLE{XuLBWG03,
	author	    = {Xu, J. H. and La Rocca, G. C. and Bassani, F. and
	  Wang, D. and Gao, J. Y.},
	title	    = {Electromagnetically induced one-photon and two-photon
	  transparency in rubidium atoms},
	journal     = {Opt. Commun.},
	year	    = {2003},
	volume	    = {216},
	pages	    = {157-164},
	abstract    = {We investigate electromagnetically induced
	  transparency (EIT) for one-photon and resonant two-photon
	  transitions in rubidium atomic vapors. One-photon transparency is
	  obtained in the 5S5P-5D three level ladder system. At the same
	  time, we study electromagnetically induced transparency in the
	  two-photon transition (EITT) from the 5S to the 7S state resonant
	  with the 5P intermediate state, when the latter is coupled to the
	  5D state by a control beam. The dependence of the transparency
	  profile on the controlling laser intensity, linewidth, and detuning
	  is investigated. Experimental results are obtained for isotopes
	  Rb-85 and Rb-87 characterized by different hyperfine structures.
	  Our findings for both the one-photon and the resonant two-photon
	  transparency agree well with the prediction from three and
	  four-level theory, respectively, with independently determined
	  spectroscopic parameters. (C) 2002 Elsevier Science B.V. All rights
	  reserved.
	  }
}

@ARTICLE{KuznetsovaKHS02,
	author	    = {Kuznetsova, E. and Kocharovskaya, O. and Hemmer, P.
	  and Scully, M. O.},
	title	    = {Atomic interference phenomena in solids with a
	  long-lived spin coherence},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {66},
	pages	    = {063802},
	abstract    = {We generalize the theory of electromagnetically
	  induced transparency (EIT) and slow group velocity for the case of
	  the homogeneous and inhomogeneous line broadening in both oneand
	  two-photon transitions which unavoidably takes place in solid
	  materials with a long-lived spin coherence. We identify regimes of
	  EIT where the linewidth can be essentially reduced due to
	  inhomogeneous broadening and, moreover, can be proportional to the
	  amplitude of the driving field rather than the intensity. We
	  suggest also a class of solid materials, namely, rare-earth ion
	  doped semiconductors or dielectrics with electricdipole allowed
	  transitions, that is very promising for realization and
	  applications of EIT.
	  }
}

@ARTICLE{PatnaikLH02,
	author	    = {Patnaik, A. K. and Liang, J. Q. and Hakuta, K.},
	title	    = {Slow light propagation in a thin optical fiber via
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {66},
	pages	    = {063808},
	abstract    = {We propose a configuration that utilizes
	  electromagnetically induced transparency (EIT) to tailor a fiber
	  mode propagating inside a thin optical fiber and coherently control
	  its dispersion properties to drastically reduce the group velocity
	  of the fiber mode. The key to this proposal is that the evanescent
	  field of the thin fiber strongly couples with the surrounding
	  active medium, so that the EIT condition is met by the medium. We
	  show how the properties of the fiber mode are modified due to the
	  EIT medium, both numerically and analytically. We demonstrate that
	  the group velocity of the modified fiber mode can be drastically
	  reduced (approximate to44 m/sec) using the coherently prepared
	  orthohydrogen doped in a matrix of parahydrogen crystal as the EIT
	  medium.}
}

@ARTICLE{JohnssonF02,
	author	    = {Johnsson, M. T. and Fleischhauer, M.},
	title	    = {Quantum theory of resonantly enhanced four-wave
	  mixing: Meanfield and exact numerical solutions},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {66},
	pages	    = {043808},
	abstract    = {We present a full quantum analysis of resonant forward
	  fourwave mixing based on electromagnetically induced transparency
	  (EIT). In particular, we study the regime of efficient nonlinear
	  conversion with low-intensity fields that has been predicted from a
	  semiclassical analysis. We derive an effective nonlinear
	  interaction Hamiltonian in the adiabatic limit. In contrast to
	  conventional nonlinear optics, this Hamiltonian does not have a
	  power expansion in the fields and the conversion length decreases
	  with decreasing input power. We analyze the stationary wave-mixing
	  process in the forward scattering configuration using an exact
	  numerical analysis for up to 10(3) input photons and compare the
	  results with a mean- field approach. Due to quantum effects,
	  complete conversion from the two pump fields into the signal and
	  idler modes is achieved only asymptotically for large coherent pump
	  intensities or for pump fields in few-photon Fock states. The
	  signal and idler fields are perfectly quantum correlated which has
	  potential applications in quantum communication schemes. We also
	  discuss the implementation of a single-photon phase gate for
	  continuous quantum computation.
	  }
}

@ARTICLE{KryachkoLT02,
	author	    = {Kryachko, A. Y. and Litvak, A. G. and Tokman, M. D.},
	title	    = {Electromagnetically induced transparency in
	  high-temperature magnetoactive plasma},
	journal     = {J. Exp. Theor. Phys.},
	year	    = {2002},
	volume	    = {95},
	pages	    = {697-704},
	abstract    = {We investigate a classical analog of
	  electromagnetically induced transparency (EIT) currently popular in
	  quantum electronics. We consider EIT for electron cyclotron waves
	  in finite-temperature plasma. We derive an expression for the
	  effective refractive index of an electromagnetic wave and study the
	  dispersion and absorption of this wave under EIT conditions.
	  Allowance for thermal motion is shown to radically change the
	  behavior of the dispersion curves for the signal wave in the EIT
	  region compared to the case of cold plasma. (C) 2002 MAIK
	  "Nauka/Interperiodica".
	  }
}

@ARTICLE{ThanopulosS02,
	author	    = {Thanopulos, I. and Shapiro, M.},
	title	    = {Slowing down of light by laser induced barrier
	  hopping},
	journal     = {J. Chem. Phys.},
	year	    = {2002},
	volume	    = {117},
	pages	    = {8404-8411},
	abstract    = {We suggest that a very significant reduction in the
	  group velocity of light occurs in a laser induced barrier-hopping
	  process, known as "Laser Catalysis.'' In this process a system is
	  made to hop over a potential barrier via a virtual transition to an
	  excited bound state. As in electromagnetically induced transparency
	  (EIT), the light absorption is predicted to dip to zero at a
	  certain frequency, thereby also changing the refractive index,
	  inducing in turn the slowing down of the group velocity of the
	  light. In contrast to EIT, a single pulse is predicted to induce
	  its own transparency and in contrast to self-induced transparency
	  the process is predicted to be insensitive to the pulse area (as
	  long as the pulse is intense enough to meet the adiabaticity
	  criterion). Thus, the medium becomes transparent to the light, as
	  the laser induced barrierhopping process brings about a
	  fundamental change in the medium. (C) 2002 American Institute of
	  Physics.
	  }
}

@ARTICLE{AhufingerCCBMF02,
	author	    = {Ahufinger, V. and Corbalan, R. and Cataliotti, F. and
	  Burger, S. and Minardi, F. and Fort, C.},
	title	    = {Electromagnetically induced transparency in a
	  Bose-Einstein condensate},
	journal     = {Opt. Commun.},
	year	    = {2002},
	volume	    = {211},
	pages	    = {159-165},
	abstract    = {We report on the direct observation of the
	  electromagnetically induced transparency (EIT) lineshape of cold
	  Rb-87 atoms above and below the transition temperature for
	  Bose-Einstein condensation (BEC). Similar results are observed in
	  both temperature regimes, with an absorption reduction of about
	  60\%. Good agreement with a theoretical model is discussed. (C)
	  2002 Elsevier Science B.V. All rights reserved.
	  }
}


@ARTICLE{MewesF02,
	author	    = {Mewes, C. and Fleischhauer, M.},
	title	    = {Two-photon linewidth of light "stopping" via
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {66},
	pages	    = {033820},
	abstract    = {We analyze the two-photon linewidth of a recently
	  proposed adiabatic transfer technique for "stopping" of light using
	  electromagnetically induced transparency (EIT). We show that a
	  successful and reliable transfer of excitation from light to atoms
	  and back can be achieved if the spectrum of the input probe pulse
	  lies within the initial transparency window of EIT, and the
	  two-photon detuning delta is less than the collective coupling
	  strength (collective vacuum Rabi frequency) grootN divided by
	  rootgammaT, with gamma being the radiative decay rate, N being the
	  effective number of atoms in the sample, and T being the pulse
	  duration. Hence in an optically thick medium light "storage" and
	  retrieval is possible with high fidelity even for systems with
	  rather large two-photon detuning or inhomogeneous broadening.
	  }
}

@ARTICLE{LiNS02,
	author	    = {Li, Y. F. and Niu, Y. P. and Sun, J. F.},
	title	    = {The effect of resonant four-wave-mixing on
	  electromagnetically induced transparency in Lambda-type system
	  employing a twophoton field},
	journal     = {Phys. Lett. A},
	year	    = {2002},
	volume	    = {301},
	pages	    = {195-202},
	abstract    = {Four-wave-mixing has been considered in a A-type
	  system to make clear the asymmetry occurred in EIT profile which
	  had been realized experimentally in Phys. Rev. A 52 (1995) 2302. We
	  present both analytical and numerical calculation to explain the
	  reason. In the case of Doppler-free for the two-photon probe field,
	  why EIT dip was not detected is also been demonstrated. (C) 2002
	  Elsevier Science B.V. All rights reserved.
	  }
}

@ARTICLE{ShvetsW02,
	author	    = {Shvets, G. and Wurtele, J. S.},
	title	    = {Transparency of magnetized plasma at the cyclotron
	  frequency},
	journal     = {Phys. Rev. Lett.},
	year	    = {2002},
	volume	    = {89},
	pages	    = {115003},
	abstract    = {Electromagnetic radiation is strongly absorbed by a
	  magnetized plasma if the radiation frequency equals the cyclotron
	  frequency of plasma electrons. It is demonstrated that absorption
	  can be completely canceled in the presence of a magnetostatic field
	  of an undulator, or a second radiation beam, resulting in plasma
	  transparency at the cyclotron frequency. This effect is reminiscent
	  of the electromagnetically induced transparency (EIT) of
	  three-level atomic systems, except that it occurs in a completely
	  classical plasma. Unlike the atomic systems, where all the excited
	  levels required for EIT exist in each atom, this classical EIT
	  requires the excitation of nonlocal plasma oscillation. A
	  Lagrangian description was used to elucidate the physics of the
	  plasma transparency and control of group and phase velocity. This
	  control leads to applications for electromagnetic pulse compression
	  and electron/ion acceleration.
	  }
}

@ARTICLE{JavanKLS02,
	author	    = {Javan, A. and Kocharovskaya, O. and Lee, H. and
	  Scully, M. O.},
	title	    = {Narrowing of electromagnetically induced transparency
	  resonance in a Doppler-broadened medium},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {66},
	pages	    = {013805},
	abstract    = {We derive an analytic expression for the linewidth of
	  electromagnetically induced transparency (EIT) resonance in a
	  Doppler-broadened system. It is shown here that for relatively low
	  intensity of the driving field the EIT linewidth is proportional to
	  the square root of intensity and is independent of the Doppler
	  width, similar to the laser-induced line narrowing effect described
	  by Feld and Javan. In the limit of high intensity we recover the
	  usual power-broadening case where the EIT linewidth is proportional
	  to the intensity and inversely proportional to the Doppler width.
	  }
}

@ARTICLE{DengHKAP02,
	author	    = {Deng, L. and Hagley, E. W. and Kozuma, M. and
	  Akamatsu, D. and Payne, M. G.},
	title	    = {Achieving very-low-loss group velocity reduction
	  without electromagnetically induced transparency},
	journal     = {Appl. Phys. Lett.},
	year	    = {2002},
	volume	    = {81},
	pages	    = {1168-1170},
	abstract    = {A Raman method is studied experimentally for potential
	  opticalwave group velocity reduction in resonant medium.
	  Specifically, we show that the proposed method can achieve
	  significant group velocity reduction comparable to the conventional
	  electromagnetically induced transparency (EIT) method that had been
	  exclusively used to date. In addition, we show that this method has
	  a significantly lower loss compared to the EIT method, and has rich
	  dynamics such as probe pulse narrowing. Such features have
	  applications in the domain of telecommunication technology. (C)
	  2002 American Institute of Physics.
	  }
}

@ARTICLE{ArtoniBCL02,
	author	    = {Artoni, M. and Bassani, F. and Carusotto, I. and La
	  Rocca, G. C.},
	title	    = {The regime of electromagnetically induced transparency
	  in optically dense media: from atoms to excitons},
	journal     = {Braz. J. Phys.},
	year	    = {2002},
	volume	    = {32},
	pages	    = {275-283},
	abstract    = {The phenomenon of electromagnetically induced
	  transparency (EIT) was discovered by Adriano Gozzini and coworkers
	  in 1976 in Pisa. Novel schemes to investigate and exploit EIT in
	  the optical domain have attracted much interest both in atomic and
	  solid state systems. We discuss some of our recent theoretical
	  results, in particular: i) a well developed EIT regime based on
	  free exciton levels in undoped bulk crystalline Cu2O; ii) light
	  dragging effects in moving media under EIT; iii) the coherent
	  control of Cherenkov radiation in the EIT regime.
	  }
}

@ARTICLE{ZhaoWXZYJ02,
	author	    = {Zhao, J. M. and Wang, L. R. and Xiao, L. T. and Zhao,
	  Y. T. and Yin, W. B. and Jia, S. T.},
	title	    = {Experimental measurement of absorption and dispersion
	  in V-type cesium atom},
	journal     = {Opt. Commun.},
	year	    = {2002},
	volume	    = {206},
	pages	    = {341-345},
	abstract    = {Electromagnetically induced transparency (EIT) is
	  observed in a three-level V-type system in cesium vapor at room
	  temperature. The absorption and dispersion properties are measured
	  under the condition that the coupling frequency is exactly
	  resonance with transition 6S(1,2) (F = 4) to 6P(3,2) (F' = 3) while
	  the probe frequency is scanned across the transitions from the
	  6S(1,2) (F = 4) to all structures of the 6P(3,2). The effects of
	  detuning of the coupling beam are studied. The results of the
	  experiment agree with the simple theoretical analysis. (C) 2002
	  Published by Elsevier Science B.V.
	  }
}

@ARTICLE{WuG02,
	author	    = {Wu, J. H. and Gao, J. Y.},
	title	    = {Absorption properties of a driven Doppler-broadened
	  ladder system with hyperfine structure},
	journal     = {Chin. Phys.},
	year	    = {2002},
	volume	    = {11},
	pages	    = {572-577},
	abstract    = {We have studied the absorption spectrum of a
	  Doppler-broadened ladder system, where the highest level is coupled
	  into two middle hyperfine sublevels by a strong coherent field. We
	  find that, when the system is considered as homogeneous, either two
	  or three spectral components are observed, depending on the
	  detuning of the coherent field. But when the velocity distribution
	  of atoms is considered, we can always observe one
	  electromagnetically induced transparency (EIT) window with high
	  dispersion. So the atomic hyperfine structure cannot be an
	  impediment for obtaining FIT.
	  }
}

@ARTICLE{DengHKP02,
	author	    = {Deng, L. and Hagley, E. W. and Kozuma, M. and Payne,
	  M. G.},
	title	    = {Optical-wave group-velocity reduction without
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {65},
	pages	    = {051805},
	abstract    = {A Raman scheme for optical-pulse group-velocity
	  reduction in a pure lifetime broadened system is studied. We show
	  that this nonelectromagnetically induced transparency (NEIT) scheme
	  has many advantages over the conventional method that critically
	  relies on the transparency window created by an EIT process.
	  Significant reduction of the group velocity, probe field loss, and
	  pulse distortion are reported. In addition, rich dynamics of the
	  propagation process are studied.
	  }
}

@ARTICLE{CardimonaH02,
	author	    = {Cardimona, D. A. and Huang, D. H.},
	title	    = {Connection of off-diagonal radiative-decay coupling to
	  electromagnetically induced transparency and amplification without
	  inversion in a three-level atomic system},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {65},
	pages	    = {033828},
	abstract    = {The equivalence between the off-diagonal
	  radiative-decay coupling (ODRDC) effect in the bare-atom picture of
	  a threelevel atomic system [see Cardimona et al., J. Phys. B 15,
	  55 (1982)] and the electromagnetically induced transparency (EIT)
	  effect in the dressed-atom picture [see Imamoglu et al., Opt. Lett.
	  14, 1344 (1989)] is uncovered and a full comparison of their
	  physical origins is given. The mechanism for both ODRDC and Harris'
	  EIT is found to be a consequence of the quantum interference
	  between a direct absorption path and an indirect absorption path
	  mediated by either a self absorption of spontaneous photons or a
	  Fano-type coupling. A connection is then pointed out between the
	  effects of probe-field gain (PFG) based on an ODRDC process [see
	  Huang et al., Phys. Rev. A 64, 013822 (2001)] and amplification
	  without inversion (AWI) [see Fearn et al., Opt. Commun. 87, 323
	  (1992)] in the bare-atom picture of a three-level atomic system.
	  The PFG effect is found as a result of transferring electrons
	  between the two upper levels due to the phase-sensitive coherence
	  provided by a laser-induced ODRDC process, while the AWI effect to
	  one of the two probe fields is attributed to its coupling to a
	  strong laser field generating an off-resonant gain through an
	  induced nonlinearity in the other probe field. Both the advantages
	  and disadvantages as well as the limitations of the ODRDC, EIT,
	  PFG, and AWI effects are discussed and compared.
	  }
}

@ARTICLE{BadgerHA01,
	author	    = {Badger, S. D. and Hughes, I. G. and Adams, C. S.},
	title	    = {Hyperfine effects in electromagnetically induced
	  transparency},
	journal     = {J. Phys. B-At. Mol. Opt. Phys.},
	year	    = {2001},
	volume	    = {34},
	pages	    = {L749-L756},
	abstract    = {The role of hyperfine structure in electromagnetically
	  induced transparency (EIT) is investigated by studying the 5S(1/2)-
	  5P(3/2)-5D(3/2,5/2) cascade system in Rb-85 and Rb-87. We show that
	  if the hyperfine splitting Delta(hfs) is larger than the Rabi
	  frequency of the coupling beam, Q, then the observed EIT spectra
	  can be modelled by adding terms corresponding to each hyperfine
	  state. However, in the strong-coupling limit, Omega(c) much greater
	  than Delta(hfs), a complete multilevel description is required.
	  }
}

@ARTICLE{AffolderbachKWTY02,
	author	    = {Affolderbach, C. and Knappe, S. and Wynands, R. and
	  Taichenachev, A. V. and Yudin, V. I.},
	title	    = {Electromagnetically induced transparency and
	  absorption in a standing wave},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {65},
	pages	    = {043810},
	abstract    = {A thermal vapor of three-level atoms irradiated by two
	  copropagating laser beams of suitable frequencies exhibits the
	  phenomenon of coherent population trapping, leading to an
	  electromagnetically induced transparency (EIT). When a mirror
	  reflects the beams back onto themselves one finds that depending on
	  the position along the resulting standing wave the fluorescence
	  intensity from the sample (cesium in our case) decreases (EIT) or
	  even increases [electromagnetically induced absorption (EIA)] with
	  a period on the centimeter scale. An intuitive picture is based on
	  the interference of coherent dark states but the explanation of the
	  EIA effect requires consideration of Doppler effects in the thermal
	  vapor. This allows for a quantitative comparison between
	  experimental and calculated results.
	  }
}

@ARTICLE{XuDJ02,
	author	    = {Xu, H. L. and Dai, Z. W. and Jiang, Z. K.},
	title	    = {Effect of concentration of the Er3+ ion on
	  electromagnetically induced transparency in Er3+: YAG crystal},
	journal     = {Phys. Lett. A},
	year	    = {2002},
	volume	    = {294},
	pages	    = {19-25},
	abstract    = {We studied the effect of Er3+ concentration on
	  electromagnetically induced transparency in two types of three-
	  level schemes-the ladder and the A models in Er3+:YAG, The
	  numerical calculations show that, under the same intensities of the
	  probe and the coupling fields, the absorption and the dispersion
	  were dramatically changed with Er3+ concentration. (C) 2002
	  Elsevier Science B.V. All rights reserved.
	  }
}

@ARTICLE{LitvakT02,
	author	    = {Litvak, A. G. and Tokman, M. D.},
	title	    = {Electromagnetically induced transparency in ensembles
	  of classical oscillators},
	journal     = {Phys. Rev. Lett.},
	year	    = {2002},
	volume	    = {88},
	pages	    = {095003},
	abstract    = {We develop a classical model of the parametric effect
	  of electromagnetically induced transparency (EIT) within the line
	  of resonance absorption of an electromagnetic wave in the medium-an
	  effect initially discovered for a quantum three-level system. On
	  the basis of this model, the EIT effect for electromagnetic waves
	  at frequencies of the electron-cyclotron resonance in a cold plasma
	  is considered. Similar to the analogous quantum scheme, the EIT
	  window in the classical model is characterized by group
	  deceleration of the reference electron-cyclotron wave.
	  }
}

@ARTICLE{SorokinG02,
	author	    = {Sorokin, P. P. and Glownia, J. H.},
	title	    = {Lasers without inversion (LWI) in Space: A possible
	  explanation for intense, narrow-band, emissions that dominate the
	  visible and/or far-UV (FUV) spectra of certain astronomical
	  objects},
	journal     = {Astron. Astrophys.},
	year	    = {2002},
	volume	    = {384},
	pages	    = {350-363},
	abstract    = {The optical or far-UV (FUV) spectra of certain objects
	  in Space are completely dominated by one or two spectrally narrow
	  emission lines, strongly suggesting that laser action of some kind
	  occurs in these objects. However, the electronic level structures
	  of the atoms/ions producing these emissions preclude the
	  possibility of maintaining population inversions on the electronic
	  transitions involved. In lasers, gain is normally produced on an
	  optical transition that is inverted, i.e. one that has more atoms
	  maintained in the upper than in the lower state, so that stimulated
	  emission can exceed stimulated absorption. However, as a result of
	  discoveries made in quantum electronics over the past 30 years or
	  so, one now knows that there are several ways to make stimulated
	  emission occur on a transition that is not inverted, i.e. to
	  realize a "laser without inversion (LWI)". This requires first
	  making the atoms non-absorbing at the lasing frequency, i.e.
	  setting up a condition of "electromagnetically induced transparency
	  (EIT)". Some recently developed EIT techniques for three-level
	  atoms are first reviewed. A simple model for a space LWI based upon
	  a gas of two-level atoms is then proposed. In this model,
	  transparency results from a form of EIT induced by the presence of
	  an intense, monochromatic, continuous-wave, laser beam tuned to the
	  frequency omega(o) of the two-level-atom transition. Amplification
	  of light at this same frequency occurs via resonant stimulated
	  hyper-Raman scattering (SHRS) and four-wave mixing (FWM), with
	  pumping energy provided by continuum starlight spectrally
	  overlapping the two outer absorption sidebands ("Mollow bands")
	  induced by the presence of the beam at omega(o). Two specific
	  examples of superintense line emission from Space are here
	  considered. These are (a) the H(alpha) emission line appearing as a
	  dominant singularity in certain reddened, early-type stars, and (b)
	  the powerful O VI (1032 Angstrom, 1038 Angstrom) emission doublet
	  that dominates the FUV emission spectra of symbiotic stars such as
	  RR Tel.}
}

@ARTICLE{JuzeliunasC02,
	author	    = {Juzeliunas, G. and Carmichael, H. J.},
	title	    = {Systematic formulation of slow polaritons in atomic
	  gases},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {65},
	pages	    = {021601},
	abstract    = {We formulate a theory of slow polaritons in atomic
	  gases and apply it to the slowing down, storing, and redirecting of
	  laser pulses in an electromagnetically induced transparency (EIT)
	  medium. The normal modes of the coupled matter and radiation are
	  determined through a full diagonalization of the dissipationless
	  Hamiltonian. Away from the EIT resonance, where the polaritons
	  acquire an excited-state contribution, lifetimes are introduced as
	  a secondary step. With detuning included various four-wave mixing
	  possibilities are analyzed. We investigate specifically the
	  possibility of reverting a stopped polariton by reversing the
	  control beam.
	  }
}

@ARTICLE{ValenteFL02,
	author	    = {Valente, P. and Failache, H. and Lezama, A.},
	title	    = {Comparative study of the transient evolution of Hanle
	  electromagnetically induced transparency and absorption resonances},
	journal     = {Phys. Rev. A},
	year	    = {2002},
	volume	    = {65},
	pages	    = {023814},
	abstract    = {The temporal evolutions of electromagnetically induced
	  transparency (EIT) and absorption (EIA) were observed in a Hanle
	  absorption experiment carried on the D-2 lines Of Rb-87 vapor by
	  suddenly turning the magnetic field on or off. The main features of
	  the experimental observations are well reproduced by a theoretical
	  model based on Bloch equation where the atomic level degeneracy has
	  been fully accounted for. Similar (opposite phase) evolutions were
	  observed at low optical-field intensities for Hanle-EIT or
	  Hanle-EIA resonances. Unlike the Hanle-EIA transients that are
	  increasingly shorter for driving field intensities approaching
	  saturation, the B not equal 0 transient of the Hanle-EIT signal at
	  large driving field intensities present a long decay time
	  approaching the atomic transit time. Such counterintuitive behavior
	  is interpreted as a consequence of the Zeno effect.}
}

@ARTICLE{LiSZW02,
	author	    = {Li, Y. F. and Sun, J. F. and Zhang, X. Y. and Wang, Y.
	  C.},
	title	    = {Laser-induced double-dark resonances and
	  double-transparencies in a four-level system},
	journal     = {Opt. Commun.},
	year	    = {2002},
	volume	    = {202},
	pages	    = {97-102},
	abstract    = {We study the generations of dark resonance and
	  electomagnetically induced transparency (EIT) effects in the
	  four-level system with two coherent fields coupling the transition
	  from upper level to a pair of ground levels and a lower excited
	  state. The quantum interference between two excited pathways
	  results in double-dark resonances and doubletransparency holes
	  with adjustable frequencies driven into the absorption spectrum in
	  the atomic system. A clear analytical explanation for our numerical
	  results is presented. It is shown that the relation of detunings of
	  two coherent fields plays an important role in the generations of
	  the coherent population trapping and EIT effects. (C) 20021
	  Elsevier Science B.V. All rights reserved.
	  }
}

@ARTICLE{WangGX02,
	author	    = {Wang, H. and Goorskey, D. J. and Xiao, M.},
	title	    = {Atomic coherence induced Kerr nonlinearity enhancement
	  in Rb vapour},
	journal     = {J. Mod. Opt.},
	year	    = {2002},
	volume	    = {49},
	pages	    = {335-347},
	abstract    = {The Kerr nonlinear index of refraction for rubidium
	  atoms is measured by using an optical ring cavity with and without
	  electromagnetically induced transparency (EIT). Significant
	  enhancement and inhibition of the Kerr nonlinear index is observed
	  near resonance with EIT. The nonlinear index of refraction is
	  measured as functions of probe and coupling frequency detunings,
	  respectively, with and without the presence of EIT. A simple
	  theoretical calculation including Doppler broadening is presented
	  and is found to be in good qualitative agreement with the
	  experimentally measured results.}
}

@ARTICLE{MatskoNW02,
	author	    = {Matsko, A. B. and Novikova, I. and Welch, G. R.},
	title	    = {Radiation trapping under conditions of
	  electromagnetically induced transparency},
	journal     = {J. Mod. Opt.},
	year	    = {2002},
	volume	    = {49},
	pages	    = {367-378},
	abstract    = {Reabsorption of spontaneously emitted photons, or
	  radiation trapping, is a process that occurs when light interacts
	  with optically thick media. It is shown, both theoretically and
	  experimentally, that this effect in optically thick atomic vapour
	  leads to a decrease in transmission of coherent laser radiation
	  propagating under conditions of electromagnetically induced
	  transparency (EIT). A simple theory is developed taking into
	  account the radiation trapping, which is in a good agreement with
	  the experimental observations and exact numerical simulation. This
	  allows better understanding of the physics of EIT in general, and
	  properties of dense coherent atomic media in particular.
	  }
}

@ARTICLE{HussKW02,
	author	    = {Huss, A. F. and Korsunsky, E. A. and Windholz, L.},
	title	    = {Phase control of electromagnetically induced
	  transparency in a double-Lambda system},
	journal     = {J. Mod. Opt.},
	year	    = {2002},
	volume	    = {49},
	pages	    = {141-155},
	abstract    = {It is experimentally demonstrated that the effect of
	  electromagnetically induced transparency (EIT) can be controlled
	  through the radiation phases. Corresponding investigations are
	  performed by exciting a sodium atomic vapour by four-frequency
	  laser radiation in a double-A configuration. In such a system the
	  nonabsorbing (dark) state, responsible for EIT, is created only for
	  particular values of the relative radiation phase. This phase
	  dependency is confirmed using three different methods of phase
	  control. Additionally, the relative phase is set at defined values
	  in order to adjust the medium to a fixed transmission behaviour.
	  }
}

@ARTICLE{WangZ02,
	author	    = {Wang, K. G. and Zhu, S. Y.},
	title	    = {Atomic storage states},
	journal     = {Chin. Phys. Lett.},
	year	    = {2002},
	volume	    = {19},
	pages	    = {56-59},
	abstract    = {We present a complete description of atomic storage
	  states which may appear in the electromagnetically induced
	  transparency (EIT). The result shows that the spatial coherence has
	  been included in the atomic collective operators and the atomic
	  storage states. In some limits, a set of multimode atomic storage
	  states has been established in correspondence with the multimode
	  Fock states of the electromagnetic field. This gives a better
	  understanding of the fact that, in EIT, the optical coherent
	  information can be preserved and recovered.}
}

@ARTICLE{AlzarMN02,
	author	    = {Alzar, C. L. G. and Martinez, M. A. G. and
	  Nussenzveig, P.},
	title	    = {Classical analog of electromagnetically induced
	  transparency},
	journal     = {Am. J. Phys.},
	year	    = {2002},
	volume	    = {70},
	pages	    = {37-41},
	abstract    = {We present a classical analog of electromagnetically
	  induced transparency (EIT). In a system of just two coupled
	  harmonic oscillators subject to a harmonic driving force, we
	  reproduce the phenomenology observed in EIT. We also describe a
	  simple experiment with two linearly coupled RLC circuits which can
	  be incorporated into an undergraduate laboratory. (C) 2002 American
	  Association of Physics Teachers.
	  }
}

@ARTICLE{ZhuL01,
	author	    = {Zhu, K. D. and Li, W. S.},
	title	    = {Electromagnetically induced transparency due to
	  exciton-phonon interaction in an organic quantum well},
	journal     = {J. Phys. B-At. Mol. Opt. Phys.},
	year	    = {2001},
	volume	    = {34},
	pages	    = {L679-L686},
	abstract    = {Using the bosonic exciton approximation, we show that
	  there exists electromagnetically induced transparency (EIT) in an
	  organic quantum well which includes the interaction of charge-
	  transfer excitons and phonons. The numerical results indicate that
	  the strong exciton-phonon interaction plays a key role in the
	  generation of the EIT. Without the exciton-phonon coupling, the EIT
	  will disappear immediately. Ultraslow light effects are also
	  discussed in this system.
	  }
}

@ARTICLE{Kofman01,
	author	    = {Kofman, A. G.},
	title	    = {Electromagnetically induced transparency and evolution
	  of a two-level system under chaotic field of arbitrary intensity},
	journal     = {Eur. Phys. J. D},
	year	    = {2001},
	volume	    = {17},
	pages	    = {153-165},
	abstract    = {The electromagnetically induced transparency (EIT)
	  with a (near-)resonant chaotic (amplitude-phase fluctuating,
	  GaussianMarkovian) coupling field is studied theoretically. The
	  Fourier transform of the steady-state EIT spectrum, which
	  determines a nonstationary probe absorption, is also considered.
	  This quantity equals the average diagonal element of the (reduced)
	  evolution operator of the coupled transition (the evolution
	  function). The exact solution in the form of a continued fraction
	  is obtained and used to perform numerical calculations. Moreover, a
	  number of approximate analytical results are obtained, which,
	  together with the results of previous publications, describe the
	  EIT and the evolution function in all possible regimes. In
	  particular, in the constructive-interference case the EIT increases
	  with the coupling-field bandwidth v at sufficiently small v. For a
	  strong field, the maximum of the transparency as a function of v is
	  less than that for a monochromatic field of the same average
	  intensity. In contrast, for a weak field, there is a range of v
	  values, where the field fluctuations do not affect the EIT. The
	  latter result is shown to hold for a broad class of stochastic
	  fields.
	  }
}

@ARTICLE{Windholz01,
	author	    = {Windholz, L.},
	title	    = {Coherent population trapping in multi-level atomic
	  systems},
	journal     = {Phys. Scr.},
	year	    = {2001},
	volume	    = {T95},
	pages	    = {81-91},
	abstract    = {Coherent population trapping (CPT) is treated in
	  multi-level systems, excited by twoor four-frequency laser light.
	  The dynamics of filling non-absorbing (dark) states is
	  investigated. In cases where all transitions involved are excited
	  (closed systems), the effect becomes dependent on the relative
	  phase of the light waves. Further electromagnetically induced
	  transparency (EIT) is described in three- and four- level systems
	  and used for effective side band generation.}
}

@ARTICLE{BhatiaWS01,
	author	    = {Bhatia, P. S. and Welch, G. R. and Scully, M. O.},
	title	    = {Laser amplification without population inversion on
	  the D-1 line of the Cs atom with semiconductor diode lasers},
	journal     = {J. Opt. Soc. Am. B-Opt. Phys.},
	year	    = {2001},
	volume	    = {18},
	pages	    = {1587-1596},
	abstract    = {The importance of lasing without inversion (LWI) in
	  comparison with the use of nonlinear optical techniques and
	  techniques based on high-intensity femtosecond light pulses to
	  generate high-frequency coherent radiation is outlined, The
	  original development and utilization of an experimental facility
	  based on semiconductor diode lasers to study the fundamental
	  aspects of LWI on the D-1 line of the Cs atom, which is rarely
	  attempted, is described. This experimental facility is used to
	  observe inversionless amplification on the D-1 line of the Cs atom
	  by use of a A atomic scheme, A combination of EIT and broadband
	  pumping of atoms from the lower to the upper level of the probe
	  transition allowed the observation of the inversionless gain.
	  Justification for the absence of inversion in the probe transition
	  is provided. We report a single-pass inversionless gain of
	  approximate to 11\% with relatively weak incoherent pumping. The
	  results show improvement over the previously reported inversionless
	  gain observed in Na, Rb, and Cs, illustrating the potential
	  advantage of using the D-1 line of Cs. (C) 2001 Optical Society of
	  America.
	  }
}

@ARTICLE{ChenLCSY01,
	author	    = {Chen, C. Y. and Liao, Y. A. and Chiu, H. Y. and Su, J.
	  J. and Yu, I. A.},
	title	    = {Observation of the quantum interference phenomenon
	  induced by interacting dark resonances},
	journal     = {Phys. Rev. A},
	year	    = {2001},
	volume	    = {6405},
	pages	    = {053806},
	abstract    = {We report an experimental observation of narrow and
	  highcontrast spectra. which are induced by interacting dark
	  resonances and have been predicted in Phys. Rev. A 60, 3225 (1999).
	  Spectra are measured with cold Rb-87 atoms produced by a
	  magneto-optical trap. In this experimental system, a coupling laser
	  and a weak probe laser form a three-level Lambda -type
	  configuration of electromagnetically induced transparency (EIT); a
	  microwave drives a magnetic-dipole transition between the fourth
	  level and the ground state that is coupled with the excited state
	  by the coupling laser. The observed spectral profile of probe
	  absorption exhibits a very sharp peak emerging inside a narrow EIT
	  dip. Such spectral feature provides more opportunities in
	  manipulating atomic-optical response.}
}

@ARTICLE{OpatrnyW01,
	author	    = {Opatrny, T. and Welsch, D. G.},
	title	    = {Cross phase modulation enhancement by coupled cavities
	  and electromagnetically induced transparency},
	journal     = {Fortschritte Phys.-Prog. Phys.},
	year	    = {2001},
	volume	    = {49},
	pages	    = {1065-1070},
	abstract    = {We propose an optical double-cavity resonator whose
	  response to a signal is similar to that observed in
	  electromagnetically induced transparency (EIT). A combination of
	  such a device with a four-level EIT medium can serve for achieving
	  large crossKerr modulation of a probe field by a signal field.
	  }
}

@ARTICLE{Ichimura01,
	author	    = {Ichimura, K.},
	title	    = {A simple frequency-domain quantum computer with ions
	  in a crystal coupled to a cavity mode},
	journal     = {Opt. Commun.},
	year	    = {2001},
	volume	    = {196},
	pages	    = {119-125},
	abstract    = {A quantum computer where quantum bits (qubits) are
	  defined in frequency domain and interaction between qubits is
	  mediated by a single cavity mode is proposed. In this quantum
	  computer, qubits can be individually addressed regardless of their
	  positions. Therefore, randomly distributed systems in space can be
	  directly employed as qubits. An application of nuclear spins in
	  rare-earth ions in a crystal for the quantum computer is
	  quantitatively analyzed. (C) 2001 Elsevier Science B.V. All rights
	  reserved.
	  }
}

@ARTICLE{OpatrnyW01,
	author	    = {Opatrny, T. and Welsch, D. G.},
	title	    = {Coupled cavities for enhancing the
	  cross-phase-modulation in electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2001},
	volume	    = {6402},
	pages	    = {023805},
	abstract    = {We propose an optical double-cavity resonator whose
	  response to a signal is similar to that of an electromagnetically
	  induced transparency (EIT) medium. A combination of such a device
	  with a four-level EIT medium can serve for achieving large cross-
	  Kerr modulation of a probe field by a signal field. This would
	  offer the possibility of building a quantum logic gate based on
	  photonic qubits. We discuss the technical requirements that are
	  necessary for realizing a probe-photon phase shift of pi caused by
	  a single-photon signal. The main difficulty is the requirement of
	  an ultralow reflectivity beam splitter, and we must be able to
	  operate a sufficiently dense cool EIT medium in a cavity.
	  }
}

@ARTICLE{ClarkevC01,
	author	    = {Clarke, J. J. and van Wijngaarden, W. A. and Chen, H.
	  X.},
	title	    = {Electromagnetically induced transparency using a vapor
	  cell and a laser-cooled sample of cesium atoms},
	journal     = {Phys. Rev. A},
	year	    = {2001},
	volume	    = {6402},
	pages	    = {023818},
	abstract    = {Electromagnetically induced transparency (EIT) was
	  observed in a mismatched-wavelength cascade system using a room
	  temperature vapor cell and laser-cooled atoms. A cw probe laser
	  beam monitored the cesium 6S(1/2)----6P(3/2) transition while
	  another cw laser coupled the 6P(3/2) state to a higher excited
	  state. The ratio of the observed Rabi frequencies for coupling to
	  the 6P(3/2)--> (11-13)D-3/2,(5/2) transitions agreed closely with
	  that predicted using the transition oscillator strengths. A
	  comparison of the EIT signals obtained using cold atoms and the
	  vapor cell is made.
	  }
}

@ARTICLE{KimKMPK01,
	author	    = {Kim, K. and Kwon, M. and Moon, H. S. and Park, H. D.
	  and Kim, J. B.},
	title	    = {Measurements of normal and anomalous dispersions in
	  coherently driven Cs vapors},
	journal     = {J. Korean Phys. Soc.},
	year	    = {2001},
	volume	    = {38},
	pages	    = {666-669},
	abstract    = {Negative and positive dispersions in transitions of
	  the C-S D-2 line have been measured by setting up a homodyne
	  Mach-Zehnder interferometer through a coherently driven atomic
	  system. Anomalous dispersion due to the electromagnetically induced
	  absorption (EIA) process and normal dispersion due to the
	  electromagnetically induced transparency (EIT) process were dn/d v
	  similar or equal to -1.8 x 10-(14) Hz(-1) and 8.7 x 10- (14)
	  Hz(-1), which corresponded to a negative group velocity v(g)
	  similar or equal to -c/14 and a positive one v(g) similar or equal
	  to c/31, respectively.
	  }
}

@ARTICLE{YanRZ01,
	author	    = {Yan, M. and Rickey, E. G. and Zhu, Y. F.},
	title	    = {Nonlinear absorption by quantum interference in cold
	  atoms},
	journal     = {Opt. Lett.},
	year	    = {2001},
	volume	    = {26},
	pages	    = {548-550},
	abstract    = {We report an experimental observation of third-order
	  nonlinear absorption by quantum interference in Rb-87 atoms cooled
	  and confined in a magneto-optic trap. A coupling laser creates
	  electromagnetically induced transparency (EIT) in a multilevel Rb
	  system in which the third-order nonlinear absorption is enhanced by
	  constructive quantum interference while the linear absorption is
	  inhibited by destructive interference. Our experiment demonstrates
	  the EIT system proposed by Harris and Yamamoto [Phys. Rev. Lett.
	  81, 3611 (1998)], which absorbs two photons but not one photon in
	  the dressed-state picture. (C) 2001 Optical Society of America.
	  }
}

@ARTICLE{McGloinFD01,
	author	    = {McGloin, D. and Fulton, D. J. and Dunn, M. H.},
	title	    = {Electromagnetically induced transparency in N-level
	  cascade schemes},
	journal     = {Opt. Commun.},
	year	    = {2001},
	volume	    = {190},
	pages	    = {221-229},
	abstract    = {We examine electromagnetically induced transparency
	  (EIT) in cascade schemes with N levels and N - 1 fields. We show
	  that transparency effects are present when N is odd and that
	  destruction of EIT is present on line centre when N is even. We
	  predict multiple dark resonances in such schemes due to multiphoton
	  EIT effects. By examining atomic rubidium we propose methods of
	  achieving such schemes by use of coupling rf fields into hyperfine
	  levels. (C) 2001 Published by Elsevier Science B.V.
	  }
}

@ARTICLE{ArtoniCLB01,
	author	    = {Artoni, M. and Carusotto, I. and La Rocca, G. C. and
	  Bassani, F.},
	title	    = {Fresnel light drag in a coherently driven moving
	  medium},
	journal     = {Phys. Rev. Lett.},
	year	    = {2001},
	volume	    = {86},
	pages	    = {2549-2552},
	abstract    = {We theoretically study how the phase of a light plane
	  wave propagating in a resonant medium under electromagnetically
	  induced transparency (EIT) is affected by the uniform motion of the
	  medium. For cuprous oxide (Cu2O), where EIT can be implemented
	  through a typical pump-probe configuration, the resonant probe beam
	  experiences a phase shift (Fresnel-Fizeau effect) that may vary
	  over a wide range of values, positive or negative, and even
	  vanishing, due to the combined effects of the strong frequency
	  dispersion and anisotropy both induced by the pump. The use of such
	  a coherently driven dragging medium may improve by at least 1 order
	  of magnitude the sensitivity at low velocity in optical drag
	  experiments.
	  }
}

@ARTICLE{BenninkBSW01,
	author	    = {Bennink, R. S. and Boyd, R. W. and Stroud, C. R. and
	  Wong, V.},
	title	    = {Enhanced self-action effects by electromagnetically
	  induced transparency in the two-level atom},
	journal     = {Phys. Rev. A},
	year	    = {2001},
	volume	    = {6303},
	pages	    = {033804},
	abstract    = {Electromagnetically induced transparency (EIT) has
	  been studied primarily within the context of multilevel atomic
	  systems. We show that EIT can occur also in a two-level atomic
	  system and can lead to strong self-action and slow-light effects
	  that are not hampered by material absorption, with important
	  potential implications for processes such as squeezed-light
	  generation and the propagation of optical solitons.
	  }
}

@ARTICLE{Kofman01,
	author	    = {Kofman, A. G.},
	title	    = {Electromagnetically induced transparency and evolution
	  of a two-level system under a strong chaotic field},
	journal     = {Phys. Rev. A},
	year	    = {2001},
	volume	    = {6303},
	pages	    = {033810},
	abstract    = {The present paper treats the electromagnetically
	  induced transparency (EIT), i.e., the absorption spectrum of a weak
	  probe field, near-resonant to a material transition, in the
	  presence of a strong amplitude-phase fluctuating field which
	  couples the upper level of the transition to another excited level.
	  The coupling field is assumed to be chaotic (i.e., a complex
	  Gaussian process with a Lorentzian spectrum) and so strong that the
	  material relaxation and the detuning can be neglected. In addition,
	  we consider the Fourier transform of the spectrum (U) over bar
	  (aa)(t), which determines absorption of a probe field with a
	  time-dependent intensity. The quantity (U) over bar (aa)(t) equals
	  a diagonal element of the average reduced evolution operator of the
	  two-level system (TLS), coupled by the strong field. As a starting
	  point, we use the stationary, partially averaged stochastic
	  Schrodinger equation, which has the form of a set of two
	  second-order differential equations. The theory is developed by
	  combining analytical and numerical approaches. For the most
	  important regime, when the rms Rabi frequency V-0 is much greater
	  than the coupling-held bandwidth nu, we obtain scaling relations
	  for the EIT line shape and the TLS evolution. In particular, the
	  absorption at the minimum (i.e., at the resonance frequency) scales
	  as nu V1/3(0)-4/3, whereas the evolution function (U) over bar
	  (aa)(t) performs damped oscillations with the decay rate on the
	  order of (V(0)(2)nu)(1/3). These results differ significantly from
	  those following from the uncorrelated-jump model. The results of
	  this paper are shown to be applicable to more general models of
	  amplitude-phase fluctuations than the Gaussian-Markovian chaotic
	  field.
	  }
}

@ARTICLE{KocharovskayaRS01,
	author	    = {Kocharovskaya, O. and Rostovtsev, Y. and Scully, M.
	  O.},
	title	    = {Stopping light via hot atoms},
	journal     = {Phys. Rev. Lett.},
	year	    = {2001},
	volume	    = {86},
	pages	    = {628-631},
	abstract    = {We prove that it is possible to freeze a light pulse
	  (i.e., to bring it to a full stop) or even to make its group
	  velocity negative in a coherently driven Doppler broadened atomic
	  medium via electromagnetically induced transparency (EIT). This
	  remarkable phenomenon of the ultraslow EIT polariton is based on
	  the spatial dispersion of the refraction index n(w,k), i.e., its
	  wave number dependence, which is due to atomic motion and provides
	  a negative contribution to the group velocity. This is related to,
	  but qualitatively different from, the recently observed light
	  slowing caused by large temporal (frequency) dispersion.
	  }
}

@ARTICLE{ScullyAKKM01,
	author	    = {Scully, M. O. and Agarwal, G. S. and Kocharovskaya, O.
	  and Kozlov, V. V. and Matsko, A. B.},
	title	    = {Mixed electromagnetically and self-induced
	  transparency},
	journal     = {Opt. Express},
	year	    = {2001},
	volume	    = {8},
	pages	    = {66-75},
	abstract    = {We show that application of self-induced transparency
	  (SIT) solitons as a driving field in V-type electromagnetically
	  induced transparency (EIT) leads to "mixed induced transparency"
	  (MIT) that nicely combines the best features of both SIT and EIT.
	  (C) 2001 Optical Society of America.}
}

@ARTICLE{WangGBX00,
	author	    = {Wang, H. and Goorskey, D. J. and Burkett, W. H. and
	  Xiao, M.},
	title	    = {Cavity-linewidth narrowing by means of
	  electromagnetically induced transparency},
	journal     = {Opt. Lett.},
	year	    = {2000},
	volume	    = {25},
	pages	    = {1732-1734},
	abstract    = {Cavity-linewidth narrowing in a ring cavity that is
	  due to the high dispersion and reduced absorption produced by
	  electromagnetically induced transparency (EIT) in rubidium-atom
	  vapor has been experimentally observed. The cavity linewidth with
	  rubidium atoms under EIT conditions can be significantly narrowed.
	  Cavity-linewidth narrowing was measured as a function of coupling
	  beam power. (C) 2000 Optical Society of America.}
}

@ARTICLE{KosachiovK00,
	author	    = {Kosachiov, D. V. and Korsunsky, E. A.},
	title	    = {Efficient microwave-induced optical frequency
	  conversion},
	journal     = {Eur. Phys. J. D},
	year	    = {2000},
	volume	    = {11},
	pages	    = {457-463},
	abstract    = {Frequency conversion process is studied in a medium of
	  atoms with a Lambda configuration of levels, where transition
	  between two lower states is driven by a microwave field. In this
	  system, conversion efficiency can be very high by virtue of the
	  effect of electromagnetically induced transparency (EIT). Depending
	  on intensity of the microwave field, two regimes of EIT are
	  realized: "dark-state" EIT for the weak field, and
	  Autler-Townes-type EIT for the strong one. We study both cases via
	  analytical and numerical solution and find optimum conditions for
	  the conversion.
	  }
}

@ARTICLE{GordonMJ00,
	author	    = {Gordon, D. F. and Mori, W. B. and Joshi, C.},
	title	    = {On the possibility of electromagnetically induced
	  transparency in a plasma. I. Infinite plasma},
	journal     = {Phys. Plasmas},
	year	    = {2000},
	volume	    = {7},
	pages	    = {3145-3155},
	abstract    = {The theory of electromagnetically induced transparency
	  (EIT) in a plasma [S. E. Harris, Phys. Rev. Lett. 77, 5357 (1996)]
	  is examined in the context of an infinite system. A new dispersion
	  relation is derived which accounts for relativistic effects in an
	  overdense plasma. Several branches of the dispersion relation are
	  plotted and discussed. Particle simulations are used to confirm the
	  findings. (C) 2000 American Institute of Physics.
	  [S1070-664X(00)00407-9].
	  }
}

@ARTICLE{GordonMJ00,
	author	    = {Gordon, D. F. and Mori, W. B. and Joshi, C.},
	title	    = {On the possibility of electromagnetically induced
	  transparency in a plasma. II. Bounded plasma},
	journal     = {Phys. Plasmas},
	year	    = {2000},
	volume	    = {7},
	pages	    = {3156-3166},
	abstract    = {The theory of electromagnetically induced transparency
	  (EIT) in a plasma [S. E. Harris, Phys. Rev. Lett. 77, 5357 (1996)]
	  is examined in the context of a bounded system. It is found via
	  particle simulations that an overdense plasma slab reflects short
	  pulses even in the presence of an EIT passband. However, a
	  two-frequency laser, or "beatwave," will cascade into a Stokes
	  satellite with a frequency below the cut-off frequency. This can
	  lead to an apparent EIT signature if a specific set of parameters
	  are chosen. (C) 2000 American Institute of Physics.
	  [S1070-664X(00)00507-3].
	  }
}

@ARTICLE{FleischhauerMS00,
	author	    = {Fleischhauer, M. and Matsko, A. B. and Scully, M. O.},
	title	    = {Quantum limit of optical magnetometry in the presence
	  of ac Stark shifts},
	journal     = {Phys. Rev. A},
	year	    = {2000},
	volume	    = {6201},
	pages	    = {013808},
	abstract    = {We analyze systematic (classical) and fundamental
	  (quantum) limitations of the sensitivity of optical magnetometers
	  resulting from ac Stark shifts. We show that in contrast to
	  absorption-based techniques, the signal reduction associated with
	  classical broadening can be compensated in magnetometers based on
	  phase measurements using electromagnetically induced transparency
	  (EIT). However due to ac Stark-associated quantum noise the
	  signal-to-noise ratio of FIT-based magnetometers attains a maximum
	  value at a certain laser intensity. This value is independent on
	  the quantum statistics of the light and defines a standard quantum
	  limit of sensitivity. We demonstrate that an EIT-based optical
	  magnetometer in Faraday configuration is the best candidate to
	  achieve the highest sensitivity of magnetic-field detection and
	  give a detailed analysis of such a device.
	  }
}

@ARTICLE{KozlovE00,
	author	    = {Kozlov, V. V. and Eberly, J. H.},
	title	    = {Ultrashort pulses in phaseonium: the interplay between
	  SIT and EIT},
	journal     = {Opt. Commun.},
	year	    = {2000},
	volume	    = {179},
	pages	    = {85-96},
	abstract    = {Pulse propagation in the pure-state three-level medium
	  called phaseonium by Marlan Scully is studied both analytically and
	  numerically. Distinctions between SIT-type pulses (e.g., simultons)
	  and EIT-type pulses are most naturally revealed by making use of
	  dark and bright dressed-state amplitudes. We show that EIT-type and
	  SIT-type pulses propagating in phaseonium are to be distinguished
	  by the type of population evolution that they induce. (C) 2000
	  Elsevier Science B.V. All rights reserved.
	  }
}

@ARTICLE{DormanKM00,
	author	    = {Dorman, C. and Kucukkara, I. and Marangos, J. P.},
	title	    = {Density dependent effects due to residual
	  susceptibilities in a four-wave mixing scheme with
	  electromagnetically induced transparency},
	journal     = {Opt. Commun.},
	year	    = {2000},
	volume	    = {180},
	pages	    = {263-270},
	abstract    = {We have studied the generation of vacuum ultraviolet
	  radiation (at 123.6 nm) produced in a resonant four-wave-mixing
	  scheme in krypton, enhanced by electromagnetically induced
	  transparency. The interplay between the non-linear susceptibility
	  (governing the wave-mixing), the linear susceptibility (governing
	  the absorption and dispersion), and the density-length product was
	  examined both experimentally and numerically. We observe favourable
	  scaling of the yield with density-length product (NL) up to a value
	  of 5 X 10(16) cm(-2). Above this NL value the yield decreases due
	  to the background wave-vector mismatch (Delta k(resid)), which
	  arises from the additional atomic energy levels outside the three
	  considered in the EIT enhanced mixing scheme. Our results suggest
	  that further enhancements in frequency up-conversion can be
	  achieved by employing a buffer gas as a phase matching agent. (C)
	  2000 Elsevier Science B.V. All rights reserved.
	  }
}

@ARTICLE{SchmidtR00,
	author	    = {Schmidt, H. and Ram, R. J.},
	title	    = {All-optical wavelength converter and switch based on
	  electromagnetically induced transparency},
	journal     = {Appl. Phys. Lett.},
	year	    = {2000},
	volume	    = {76},
	pages	    = {3173-3175},
	abstract    = {We propose a method for all-optical switching and
	  wavelength conversion using electromagnetically induced
	  transparency (EIT). We discuss the mechanism for the transfer of
	  information in this scheme and determine the conditions for which
	  NxN wavelength conversion can be realized. We compare the
	  properties and limits of an EIT-based switch to conventional
	  wavelength converters. (C) 2000 American Institute of Physics.
	  [S0003-6951(00)03022-9].
	  }
}

@ARTICLE{ChenLY00,
	author	    = {Chen, Y. C. and Lin, C. W. and Yu, I. A.},
	title	    = {Role of degenerate Zeeman levels in
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2000},
	volume	    = {6105},
	pages	    = {053805},
	abstract    = {We have observed various Lambda-type
	  electromagnetically induced transparency (EIT) spectra in
	  laser-cooled Rb-87 atoms of different laser polarization
	  configurations. Unexpected profiles occur in the EIT spectra. We
	  have found the degenerate Zeeman sublevels are responsible for
	  these profiles. The experimental data are in good agreement with
	  the results from the theoretical calculation which takes into
	  account all the 13 Zeeman levels in the Lambda system. Our study
	  demonstrates that Zeeman sublevels play important roles in quantum
	  interference phenomena such as EIT and amplification without
	  population inversion (AWI), and should be taken into account in the
	  analysis of these phenomena.
	  }
}

@ARTICLE{EntinRBB00,
	author	    = {Entin, V. M. and Ryabtsev, I. I. and Boguslavskii, A.
	  E. and Beterov, I. M.},
	title	    = {Experimental implementation of a four-level N-type
	  scheme for the observation of electromagnetically induced
	  transparency},
	journal     = {Jetp Lett.},
	year	    = {2000},
	volume	    = {71},
	pages	    = {175-177},
	abstract    = {A nondegenerate four-level N-type scheme was
	  experimentally implemented to observe electromagnetically induced
	  transparency (EIT) at the Rb-87 D-2 line. Radiations of two
	  independent external-cavity semiconductor lasers were used in the
	  experiment, the current of one of them being modulated at a
	  frequency equal to the hyperfine-splitting frequency of the excited
	  5P(3/2) level. In this case, apart from the main EIT dip
	  corresponding to the two-photon Raman resonance in a threelevel
	  Lambda-scheme, additional dips detuned from the main dip by a
	  frequency equal to the frequency of the HF generator were observed
	  in the absorption spectrum. These dips were due to an increase in
	  the medium transparency at frequencies corresponding to the
	  three-photon Raman resonances in four- level N-type schemes. The
	  resonance shapes are analyzed as functions of generator frequency
	  and magnetic field. (C) 2000 MAIK "Nauka/Interperiodica".
	  }
}

@ARTICLE{PodshivalovMOSW99,
	author	    = {Podshivalov, A. A. and Matveev, O. I. and Omenetto, N.
	  and Smith, B. W. and Winefordner, J. D.},
	title	    = {Laser-induced population depletion effects in double
	  resonance excitation with Hg-202 vapors},
	journal     = {Spectroc. Acta Pt. B-Atom. Spectr.},
	year	    = {1999},
	volume	    = {54},
	pages	    = {2157-2165},
	abstract    = {By monitoring the green fluorescence transition of
	  mercury vapor 7 S-3(1) --> 6 P-3(2)0 (546.074 nm) excited by two
	  pulsed dye lasers tuned at two connected atomic resonant
	  frequencies, i.e. 6 S-1(0) --> 6 P-3(1)0 (253.652 nm) and 6 P-3(1)0
	  --> 7 S3(1) (435.835 nm), a decrease in the green fluorescence
	  yield is experimentally observed when the intensity of the
	  435.835-nm excitation transition exceeds similar to 5 kW/cm(2). A
	  similar result is obtained at the yellow fluorescence transition 6
	  D- 3(1) --> 6 P-1(1)0 (578.967 nm) when the second step is tuned to
	  the 6 P-3(1)0 --> 6 D-3(1) transition (313.159 nm). At the same
	  time, an increase in the transmittance of the ground state
	  transition (253.652 nm) is observed. It is speculated that this
	  effect, which occurs only when both laser pulses are temporally
	  coincident, and is therefore not due to photoionization, can be
	  ascribed to the existence of laser induced effects, such as a.c.
	  Stark splitting of levels and possibly electromagnetically-induced
	  transparency (EIT). Our experiment does not allow us to distinguish
	  between these two effects, nor their quantitative evaluation,
	  However, it is stressed that one cannot overlook them in those
	  atomic multi-step excitation experiments in low collisional
	  environments where a depletion of an intermediate level is
	  involved, as for example in the case of atomic fluorescence: dip
	  spectroscopy or atomic multistep and multiphoton resonance
	  ionization spectroscopy. (C) 1999 Published by Elsevier Science
	  B.V. All rights reserved.
	  }
}

@ARTICLE{BentleyLL00,
	author	    = {Bentley, C. L. and Liu, J. R. and Liao, Y.},
	title	    = {Cavity electromagnetically induced transparency of
	  driventhree-level atoms: A transparent window narrowing below a
	  natural width},
	journal     = {Phys. Rev. A},
	year	    = {2000},
	volume	    = {6102},
	pages	    = {023811},
	abstract    = {Steady-state dynamics of a Lambda atom in a ring
	  cavity driven by two coherent fields are studied for arbitrary
	  detunings, arbitrary incoherent pumping, and coherent driving
	  intensities. Effects of both cavity and effective atom number on
	  electromagnetically induced transparency (EIT) are pointed out. New
	  physical pictures for cavity EIT are given in terms of collective
	  cooperative coefficients and dispersion experienced by the probe.
	  In the regime of smaller collective cooperative coefficients, an
	  absorption-gain profile is reduced to that of a general EIT
	  estimated by the imaginary part of a corresponding dipole moment,
	  and its transparency window is directly proportional to power
	  broadening, if the total Rabi frequency is large enough. But in the
	  region of larger collective cooperative coefficients which means a
	  dense atomic medium, longer optical path, or high-Q cavity, EIT is
	  determined not only by the imaginary part but also by the real part
	  of the corresponding dipole moment, which results in the
	  possibility of observing an EIT central peak with a subnatural
	  width, while there may be nearly no power broadening.}
}

@ARTICLE{WernerI00,
	author	    = {Werner, M. J. and Imamoglu, A.},
	title	    = {Photon-photon interactions in cavity
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {2000},
	volume	    = {6001},
	pages	    = {011801},
	abstract    = {Dissipation-free photon-photon interaction at the
	  single-photon level is studied in the context of cavity
	  electromagnetically induced transparency (EIT). For a single
	  multilevel atom exhibiting EIT in the strong cavity-coupling
	  regime, the anharmonicity of the atom-cavity system has an upper
	  bound determined by single atom-photon coupling strength. A photon
	  blockade effect is inferred to occur for both singleand multiatom
	  cases from the behavior of transition rates between dressed states
	  of the system. Numerical calculations of the second-order coherence
	  function indicate that photon antibunching in both single- and
	  two-atom cases are strong and comparable.
	  }
}

@ARTICLE{DongG00,
	author	    = {Dong, P. and Gao, J. Y.},
	title	    = {Appearance and disappearance of hole-burning behind an
	  electromagnetically induced transparency window},
	journal     = {Phys. Lett. A},
	year	    = {2000},
	volume	    = {265},
	pages	    = {52-57},
	abstract    = {We propose a new scheme of hole-burning when a strong
	  coherent field, which makes an Electromagnetically Induced
	  Transparency (EIT) window, could make more or disappearance of
	  hole-burning in a Doppler broadening medium under different
	  conditions. (C) 2000 Published by Elsevier Science B.V. ALI rights
	  reserved.}
}

@ARTICLE{BentleyL99,
	author	    = {Bentley, C. L. and Liu, J. R.},
	title	    = {LWI in a driven Lambda three-level atom and effects of
	  the probe laser on EIT},
	journal     = {Opt. Commun.},
	year	    = {1999},
	volume	    = {169},
	pages	    = {289-299},
	abstract    = {Steady-state dynamics of a Lambda atom driven by two
	  coherent fields is studied for arbitrary detunings, arbitrary
	  incoherent pumping and coherent driving intensities. Effects of a
	  strong probe on EIT are worked out. Features of EFT and LWI are
	  presented in a new physical picture on the basis of the concepts of
	  quantum interference and coherence. In the weak field regime, an
	  absorption-gain profile is the subtraction of two Lorentzians with
	  the same central frequency but different widths and heights. This
	  case is mostly the result of quantum interference and coherence
	  rather than the result of AutlerTownes level splitting. In a
	  strong field regime, however, the profile is the addition of two
	  Lorentzian-like components with different central frequencies but
	  the same width, where Autler- Townes splitting and quantum
	  interference are equally important. (C) 1999 Published by Elsevier
	  Science B.V. All rights reserved.
	  }
}

@ARTICLE{WeiM99,
	author	    = {Wei, C. J. and Manson, N. B.},
	title	    = {Observation of the dynamic Stark effect on
	  electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {60},
	pages	    = {2540-2546},
	abstract    = {Using electron-spin-resonance transitions within the
	  nitrogenvacancy center in diamond, we have obtained a sharp
	  electromagnetically induced transparency (EIT) feature when the
	  coupling and probing fields satisfy a two-photon resonance
	  condition. In this paper it is shown that by the application of an
	  additional driving field the sharp EIT feature can be split into a
	  doublet or a triplet depending on the experimental configuration.
	  The results are interpreted in terms of dynamic Stark splitting of
	  the EIT feature, and the spectra are shown to be related to
	  Autler-Townes and Mellow spectra. [S1050- 2947(99)10209-9].
	  }
}

@ARTICLE{MoonKKK99,
	author	    = {Moon, H. S. and Kim, H. A. and Kim, B. S. and Kim, J.
	  B.},
	title	    = {Electromagnetically induced transparency in an ideal
	  threelevel system in Rb-87 atoms},
	journal     = {J. Korean Phys. Soc.},
	year	    = {1999},
	volume	    = {35},
	pages	    = {207-211},
	abstract    = {We have suggested an ideal three-level system, which
	  is the transition between the magnetic F = 1 and F' = 1 sublevels
	  in the Rb-87 atom, for studying atomic coherence, and we have
	  studied the electromagnetically induced transparency(EIT) in that
	  system. With two counter-rotating circularly polarized lasers,
	  Doppler-free absorption reduction in an ideal R-type three-level
	  atomic system is observed up to 95 \%, including optical pumping.
	  After adding an incoherent repumping beam from F = 2 to F = 1
	  through F' = 2, the maximum absorption reduction is approximately
	  the same as 95 \%. In a magnetic field, EIT shows dispersion-like
	  spectrum because of the detuning effect of the coupling laser due
	  to Zeeman splitting of the magnetic sublevels.
	  }
}

@ARTICLE{WeiM99,
	author	    = {Wei, C. J. and Manson, N. B.},
	title	    = {Observation of electromagnetically induced
	  transparency within an electron spin resonance transition},
	journal     = {J. Opt. B-Quantum Semicl. Opt.},
	year	    = {1999},
	volume	    = {1},
	pages	    = {464-468},
	abstract    = {A sharp transparency feature is induced in an allowed
	  electron spin resonance (ESR) transition by driving a nominally
	  spinforbidden transition. The width of the feature is narrower
	  than the homogeneous linewidth of the ESR transition and is
	  interpreted as being associated with electromagnetically induced
	  transparency (EIT). Measurements are made for the nitrogen-vacancy
	  centre in diamond and the signals are detected using a coherent
	  optical technique.
	  }
}

@ARTICLE{HamHKS99,
	author	    = {Ham, B. S. and Hemmer, P. R. and Kim, M. K. and
	  Shahriar, S. M.},
	title	    = {Quantum interference and its potential applications in
	  a spectral hole-burning solid},
	journal     = {Laser Phys.},
	year	    = {1999},
	volume	    = {9},
	pages	    = {788-796},
	abstract    = {We have reviewed observations of electromagnetically
	  induced transparency (EIT) in solids and its potential applications
	  such as enhanced four-wave mixing, Raman excited optical memory,
	  and rf-coupled optical gain.
	  }
}

@ARTICLE{SchmidtNCMGI99,
	author	    = {Schmidt, H. and Nikonov, D. E. and Campman, K. L. and
	  Maranowski, K. D. and Gossard, A. C. and Imamoglu, A.},
	title	    = {Quantum interference in semiconductor quantum wells},
	journal     = {Laser Phys.},
	year	    = {1999},
	volume	    = {9},
	pages	    = {797-812},
	abstract    = {We present a review of theoretical and experimental
	  evidence for quantum interference in intersubband transitions of
	  coupled semiconductor quantum wells. Intersubband absorption
	  spectra are calculated using semiconductor Bloch equations to
	  include the Coulomb interaction between the conduction band
	  electrons. We demonstrate that the absorption spectra must be
	  viewed as collective excitations. In a configuration analogous to
	  electromagnetically induced transparency (EIT) in atomic systems,
	  we show that quantum interference occurs between the levels of
	  these collective intersubband excitations rather than single
	  electronic states. Experiments which demonstrate quantum
	  interference in coupled quantum wells due to tunneling induced
	  transparency (TIT) are presented. The design issues for such
	  samples are reviewed, and the effects of monolayer growth
	  fluctuations on the spectra are simulated. Finally, we discuss the
	  temperature dependence of TIT and demonstrate that the quantum
	  interference persists at room temperature.
	  }
}

@ARTICLE{BoonZMD99,
	author	    = {Boon, J. R. and Zekou, E. and McGloin, D. and Dunn, M.
	  H.},
	title	    = {Comparison of wavelength dependence in cascade-,
	  Lambda-, and Vee-type schemes for electromagnetically induced
	  transparency},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {59},
	pages	    = {4675-4684},
	abstract    = {We present a theoretical study of the effects of
	  mismatching wavelengths for the coupling and probe fields in
	  Dopplerbroadened media for the three basic energy level
	  configurations commonly used to realize electromagnetically induced
	  transparency (EIT). Three wavelength regimes are considered:
	  mismatched wavelengths for which the coupling frequency is greater
	  than the probe frequency, matched wavelengths for which the
	  coupling and probe frequencies are equal, and mismatched
	  wavelengths for which the probe frequency is greater than the
	  coupling frequency. The transparency that may be induced in these
	  regimes is compared for the cascade-, Lambda-, and Vee- type
	  systems. We show that in the first mismatched regime (lambda(c) <
	  lambda(p)) EIT is possible in all schemes and is in fact stronger
	  than in the matched case. It is also demonstrated that for the
	  second mismatched regime (lambda(c) > lambda(p)) EIT can be
	  realized most readily in the Vee-type configuration in the presence
	  of Doppler broadening. These predictions are explained by
	  considering the absorption as a function of both the probe field
	  detuning and the atomic velocity. [S1050-2947(99)01006-9].
	  }
}

@ARTICLE{MitsunagaI99,
	author	    = {Mitsunaga, M. and Imoto, N.},
	title	    = {Observation of an electromagnetically induced grating
	  in cold sodium atoms},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {59},
	pages	    = {4773-4776},
	abstract    = {We have observed diffraction signals by a grating
	  originating from electromagnetically induced transparency (EIT) in
	  a threelevel Lambda system of cold sodium atoms. Theoretical and
	  experimental analyses of this phenomenon, called the
	  electromagnetically induced grating (EIG), have revealed that EIG
	  spectra exhibit background-free, Lorentzian signal profiles
	  regardless of the pump frequencies, making a clear contrast to the
	  case of ordinary EIT spectra.
	  }
}

@ARTICLE{SadeghiM99,
	author	    = {Sadeghi, S. M. and Meyer, J.},
	title	    = {Two-field electromagnetically induced transparency and
	  switching between ultranarrow absorption and gain features in
	  rubidium atoms},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {59},
	pages	    = {3998-4004},
	abstract    = {We study the generation of an ultranarrow gain
	  spectrum in an atomic transition when the upper transition level is
	  coupled to the lower transition level by one laser and to a
	  metastable state by another laser. It is shown that this spectrum
	  switches abruptly into an ultranarrow absorption line with an
	  increase in the first laser intensity. These results are explained
	  by investigating the electromagnetically induced transparency (EIT)
	  in a system where the upper transition level is coupled to two
	  metastable states by two laser fields (ir; system). We discuss
	  various features of such a transparency and show how it can be
	  described as a structuring process, similar to the laser-induced
	  continuum structure. Utilizing such a description of EIT, we
	  explain the ultranarrow gain generation as a stimulated Rayleigh
	  scattering process. [S1050-2947(99)048052].
	  }
}

@ARTICLE{HamSH99,
	author	    = {Ham, B. S. and Shahriar, S. M. and Hemmer, P. R.},
	title	    = {Electromagnetically induced transparency over spectral
	  holeburning temperature in a rare-earth-doped solid},
	journal     = {J. Opt. Soc. Am. B-Opt. Phys.},
	year	    = {1999},
	volume	    = {16},
	pages	    = {801-804},
	abstract    = {We have observed electromagnetically induced
	  transparency (EIT) in rare-earth Pr3+-doped Y2SiO5 over the
	  spectral hole-burning temperature. The transmission of the probe
	  laser beam is increased by a factor of exp(1.4) at 12 K when a
	  coupling laser of 1.2 kW/cm(2) is applied to the system. The
	  observation of EIT over the spectral hole-burning temperature in a
	  rare-earthdoped solid represents important progress toward
	  high-density echo-based optical memories at higher temperatures.
	  (C) 1999 Optical Society of America [S0740-3224(99)01605-7].
	  }
}

@ARTICLE{Kofman99,
	author	    = {Kofman, A. G.},
	title	    = {Intensity-fluctuation-induced spectral structure},
	journal     = {Europhys. Lett.},
	year	    = {1999},
	volume	    = {46},
	pages	    = {164-170},
	abstract    = {Electromagnetically induced transparency (EIT) with
	  chaotic field is considered for the constructive-interference case
	  (i.e.,when the material transition is much narrower than the
	  coupled one). The field intensity fluctuations are shown to induce
	  a narrow peak at the material frequency in addition to the familiar
	  Antler-Towns doublet. The dependence of the fluctuation-induced
	  peak on the field bandwidth nu is obtained analytically and
	  numerically. EIT is shown to increase with nu for sufficiently
	  small nu.
	  }
}

@ARTICLE{TokarykZS99,
	author	    = {Tokaryk, D. W. and Zhang, G. Z. and Stoicheff, B. P.},
	title	    = {Nonlinear optical generation in a hydrogen discharge},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {59},
	pages	    = {3116-3119},
	abstract    = {Sum-frequency generation with electromagnetically
	  induced transparency (EIT) has been examined in a hydrogen
	  discharge. EIT is demonstrated in the 3p-1s and 4p-1s transitions
	  at 102.6 and 97.3 nln, respectively, with increased efficiency of
	  generation arising from higher H-atom density, although competing
	  effects due to the presence of Hz distort the line shapes of these
	  spectra. Only for shorter-wavelength transitions (such as 7p-1s and
	  8p-1s) that show very large shifts and distortions is there a
	  decrease in intensity in comparison with generated radiation from H
	  atoms external to the discharge. [S1050-2917(99)01404-3].
	  }
}

@ARTICLE{KorsunskyLHBW99,
	author	    = {Korsunsky, E. A. and Leinfellner, N. and Huss, A. and
	  Baluschev, S. and Windholz, L.},
	title	    = {Phase-dependent electromagnetically induced
	  transparency},
	journal     = {Phys. Rev. A},
	year	    = {1999},
	volume	    = {59},
	pages	    = {2302-2305},
	abstract    = {We report on the experimental demonstration of
	  phase-dependent electromagnetically induced transparency (EIT).
	  This effect is based on a quantum interference in closed-loop
	  schemes of interaction of atoms with the radiation. It allows us to
	  control optical properties of the medium by the phases of the laser
	  fields. We discuss some of the possible applications of
	  phase-dependent EIT. [S1050-2947(99)01003-3].
	  }
}

@ARTICLE{Fleischhauer99,
	author	    = {Fleischhauer, M.},
	title	    = {Electromagnetically induced transparency and
	  coherent-state preparation in optically thick media},
	journal     = {Opt. Express},
	year	    = {1999},
	volume	    = {4},
	pages	    = {107-112},
	abstract    = {The preparation of an optically dense ensemble of
	  three-level systems in dark states of the interaction with coherent
	  radiation is discussed. It is shown that methods involving
	  spontaneous emissions of photons such as Raman optical pumping fail
	  to work beyond a critical density due to multiple scattering and
	  trapping of these photons and the associated decay of the dark
	  state(s). In optically thick media coherentstate preparation is
	  only possible by entirely coherent means such as stimulated Raman
	  adiabatic passage (STIRAP). It is shown that STIRAP is the
	  underlying physical mechanism for electromagnetically induced
	  transparency (EIT). (C) 1998 Optical Society of America.
	  }
}

@ARTICLE{IchimuraYG98,
	author	    = {Ichimura, K. and Yamamoto, K. and Gemma, N.},
	title	    = {Evidence for electromagnetically induced transparency
	  in a solid medium},
	journal     = {Phys. Rev. A},
	year	    = {1998},
	volume	    = {58},
	pages	    = {4116-4120},
	abstract    = {Strong evidence indicating the occurrence of
	  electromagnetically induced transparency (EIT) in a solid medium
	  was found. Fluorescence reduction due to Err was observed in
	  solids. The excitation intensity dependence of the fluorescence
	  reduction was found to be consistent with theoretical predictions
	  for EIT. It was experimentally demonstrated that the essential
	  condition for the observation of EIT in solids is that the Rabi
	  frequency of excitation must be larger than the inhomogeneous width
	  of the transition between the two states coupled to the third state
	  by the pair of optical fields. [S1050-2947(98)00311-9].
	  }
}

@ARTICLE{DormanM98,
	author	    = {Dorman, C. and Marangos, J. P.},
	title	    = {Resonant sum-difference frequency mixing enhanced by
	  electromagnetically induced transparency in krypton},
	journal     = {Phys. Rev. A},
	year	    = {1998},
	volume	    = {58},
	pages	    = {4121-4132},
	abstract    = {We report experiments that investigate the generation
	  of coherent VUV radiation at 123.6 nm via a resonant sum-
	  difference frequency mixing scheme in Kr. One of the mixing fields
	  at 212.55 nm was in two-photon resonance with the transition
	  between the 4p(6) S-1 ground state and the 4p(5) 5p[0,1/2] excited
	  state (94 093.7 cm(-1)). The second field (the coupling field) at
	  759 nm was in single-photon resonance with the transition between
	  the 4p(5) 5p[0,1/2] state and the 4p(5) 5s[1,1/2] state at 80 917.6
	  cm(-1). The presence of the coupling field leads to
	  electromagnetically induced transparency (EIT) at the wavelength of
	  the generated field, 123.6 nm. This is predicted to enhance the
	  four-wave-mixing efficiency by a large factor. We have studied the
	  dependence of the four-wave mixing process on the detuning and
	  strength of the coupling field. The efficiency for four-wave mixing
	  was found to be enhanced by a significant factor (>5) by the EIT
	  effect when the resonant coupling field strength exceeded about
	  half the Doppler width (0.1 cm(-1)). A calculation for
	  monochromatic fields and a uniform slab of gas provided qualitative
	  agreement with the results of experiment. The relative conversion
	  efficiency for this resonant mixing scheme is found to be 10(4)
	  times greater than that for a similar scheme where the coupling
	  laser is tuned far (1270 cm(-1)) off resonance. A substantial part
	  of this resonant enhancement can thus be attributed to the EIT
	  effect. [S1050-2947(98)00511-3].}
}

@ARTICLE{YamamotoIG98,
	author	    = {Yamamoto, K. and Ichimura, K. and Gemma, N.},
	title	    = {Enhanced and reduced absorptions via quantum
	  interference: Solid system driven by a rf field},
	journal     = {Phys. Rev. A},
	year	    = {1998},
	volume	    = {58},
	pages	    = {2460-2466},
	abstract    = {We observed quantum interference effects in
	  steady-state optical absorption in a V-type three-level system of
	  Pr3+:YAlO3 where a hyperfine transition between two upper levels
	  was homogeneously broadened by pure dephasing. This V-type system
	  was excited by a single driving radio-frequency (rf) field and two
	  probe laser fields (quantum-beat scheme). The probe absorption was
	  constructively or destructively affected by the phase of the
	  driving rf field. In contrast, under two-laser excitation without
	  application of the rf, no absorption change due to
	  electromagnetically induced transparency (EIT) was observed. A
	  comparison of observations and theoretical predictions revealed
	  that the quantum-beat scheme generates quantum interference even
	  when the dephasing rate between the two upper levels is comparable
	  with the Rabi frequency of the probe laser, and completely destroys
	  EIT.
	  }
}

@ARTICLE{ChenDMV98,
	author	    = {Chen, H. X. and Durrant, A. V. and Marangos, J. P. and
	  Vaccaro, J. A.},
	title	    = {Observation of transient electromagnetically induced
	  transparency in a rubidium Lambda system},
	journal     = {Phys. Rev. A},
	year	    = {1998},
	volume	    = {58},
	pages	    = {1545-1548},
	abstract    = {Observation of transient effects in
	  electromagnetically induced transparency (EIT) is reported in Rb-85
	  cooled in a magnetooptical trap. The transmission of a weak probe
	  beam in resonance with the 5S(1/2)(F=3) to 5P(3/2)(F=3) hyperfine
	  transition increased transiently when a relatively strong coupling
	  field in resonance with the 5S(1/2)(F=2) to 5P(3/2)(F=3) hyperfine
	  transition was switched on rapidly using a Pockels cell. The probe
	  transient showed an initial Rabi half-cycle overshoot before
	  settling down to steady-state EIT. The results agreed well with
	  computations using a three-state model of the Lambda system. The
	  computations also suggest that transient gain should be observed
	  with coupling field power only four times larger than that
	  presently available to us. [S1050-2947(98)03308-3].
	  }
}

@ARTICLE{SchmidtI98,
	author	    = {Schmidt, H. and Imamoglu, A.},
	title	    = {High-speed properties of a phase-modulation scheme
	  based on electromagnetically induced transparency},
	journal     = {Opt. Lett.},
	year	    = {1998},
	volume	    = {23},
	pages	    = {1007-1009},
	abstract    = {Recently a cross-phase modulation scheme that yields
	  giant Kerr nonlinearities by use of an electromagnetically induced
	  transparency (EIT) was proposed [Schmidt and Imamoglu, Opt. Lett.
	  21, 1936 (1996)]. We analyze the high-speed properties of this
	  scheme for short-pulse propagation. the high-speed properties of
	  this scheme for short-pulse propagation. system and show that for
	  short pulses one-photon losses are dominant. We demonstrate that
	  over the entire width the attainable phase shift in an EIT scheme
	  with a quasi-cm coupling field is orders of magnitude higher than
	  in a conventional three-level scheme or in EIT schemes, in which
	  matched pulses are used to create the transparency. (C) 1998
	  Optical Society of America.}
}

@ARTICLE{LeeS98,
	author	    = {Lee, H. and Scully, M. O.},
	title	    = {The physics of EIT and LWI in V-type configurations},
	journal     = {Found. Phys.},
	year	    = {1998},
	volume	    = {28},
	pages	    = {585-600},
	abstract    = {We review the concepts and the physics behind
	  electromagnetically induced transparency (EIT) and lasing without
	  inversion (LWI) for various models of the V-type configurations.
	  }
}

@ARTICLE{BaluschevLKW98,
	author	    = {Baluschev, S. and Leinfellner, N. and Korsunsky, E. A.
	  and Windholz, L.},
	title	    = {Electromagnetically induced transparency in a sodium
	  vapour cell},
	journal     = {Eur. Phys. J. D},
	year	    = {1998},
	volume	    = {2},
	pages	    = {5-10},
	abstract    = {The report on an investigation of electromagnetically
	  induced transparency (EIT) in sodium vapour. In our experiment,
	  sodium atoms are excited on the D-1-line with laser radiation
	  containing two components with a frequency difference close to that
	  of the two hyperfine ground states of sodium (1.772 GHz). Such an
	  excitation leads to coherent trapping of atomic population in
	  "dark" superpositional states, which dramatically reduces the
	  absorption of light. A frequency transparency window is measured to
	  have a subnatural width, which is a clear indication of coherent
	  population trapping. Dependence of EIT on laser frequencies and
	  intensities, on the magnetic field strength as well as on the
	  temperature of the sodium vapour is studied.
	  }
}

@ARTICLE{DormanMP98,
	author	    = {Dorman, C. and Marangos, J. P. and Petch, J. C.},
	title	    = {Investigation of vacuum ultraviolet generation in a
	  resonant four-wave mixing scheme in krypton with
	  electromagnetically induced transparency},
	journal     = {J. Mod. Opt.},
	year	    = {1998},
	volume	    = {45},
	pages	    = {1123-1135},
	abstract    = {We report experiments investigating a resonant
	  sum-difference frequency mixing scheme in krypton producing
	  coherent radiation at 123.6 nm (i.e. in the vacuum ultraviolet
	  (VUV)). Owing to the resonant nature of this scheme,
	  electromagnetically induced transparency (EIT) plays a crucial role
	  in the generation of this coherent radiation, resulting in a
	  greatly enhanced conversion efficiency. This is the first time a
	  resonant sumdifference mixing scheme involving EIT, that
	  generates VUV radiation, has been investigated experimentally. Our
	  results are in broad agreement with theoretical predictions.
	  Measurements are presented of the dependence of VUV generation on
	  laser detuning (in the range +/-3 cm(-1)) and laser powers. In
	  particular the dependence on the coupling field strength has been
	  studied in the range of coupling held Rabi frequencies Omega(c) =
	  0.05-3 cm(-1). We estimate an enhancement in the conversion
	  efficiency, compared with the non-resonant case, of greater than
	  10(2).
	  }
}

@ARTICLE{CroninWLF98,
	author	    = {Cronin, A. D. and Warrington, R. B. and Lamoreaux, S.
	  K. and Fortson, E. N.},
	title	    = {Studies of electromagnetically induced transparency in
	  thallium vapor and possible utility for measuring atomic parity
	  nonconservation},
	journal     = {Phys. Rev. Lett.},
	year	    = {1998},
	volume	    = {80},
	pages	    = {3719-3722},
	abstract    = {Motivated by the potential use of electromagnetically
	  induced transparency (EIT) to measure atomic parity nonconservation
	  (PNC), we have studied EIT and associated optical rotation for a
	  three-level system in thallium vapor. EIT allows sub-Doppler
	  resolution of the 6P(1/2) --> 6P(3/2) mixed magnetic dipole,
	  electric quadrupole transition at 1.28 mu m when 0.535-mu m
	  radiation acts on the 6P(3/2) --> 7S(1/2) transition. Our
	  measurements include rotation due to electromagnetically induced
	  birefringence and Faraday rotation perturbed by EIT. We also
	  identify a new method for determining the amplitude ratio E2/M1 for
	  the 1.28-mu m transition. The possible advantages of an EIT
	  technique for measuring atomic PNC are discussed in the context of
	  our results.
	  }
}

@ARTICLE{KuhnSB98,
	author	    = {Kuhn, A. and Steuerwald, S. and Bergmann, K.},
	title	    = {Coherent population transfer in NO with pulsed lasers:
	  the consequences of hyperfine structure, Doppler broadening and
	  electromagnetically induced absorption},
	journal     = {Eur. Phys. J. D},
	year	    = {1998},
	volume	    = {1},
	pages	    = {57-70},
	abstract    = {Coherent population transfer between vibrational
	  levels of the NO molecule induced by the interaction of two delayed
	  laser pulses, also referred to as stimulated Raman scattering
	  involving adiabatic passage (STIRAP), is studied experimentally in
	  a molecular beam and in the bulk. The consequences of hyperfine
	  splitting and Doppler broadening are discussed in detail. Unlike in
	  previous studies of this kind, transfer occurs simultaneously
	  between more than one group of non degenerate levels. In a
	  molecular beam or in the bulk, the transfer efficiency of STIRAP
	  exceeds that, obtained by Stimulated Emission Pumping (SEP) by a
	  factor of 3.6 or 15, respectively. We estimate the absolute
	  transfer efficiency T in the beam to be T approximate to 60\%,
	  while T approximate to 18\% is found in the bulk. In both cases:
	  this is 60\% of the maximum value expected from numerical studies.
	  Possible reasons for this discrepancy are discussed. Finally we
	  show that the absorption of a pump pulse in a weakly absorbing
	  medium is significantly enhanced by the presence of a copropagating
	  Stokes pulse when the Rabi frequency Omega s of the latter is
	  smaller than the width of the Doppler profile Delta nu(D). The
	  relation of this observation to the phenomenon of
	  Electromagnetically Induced Transparency (EIT), which is observed
	  for Omega s >> Delta nu(D), is also discussed.}
}

@ARTICLE{Marangos98,
	author	    = {Marangos, J. P.},
	title	    = {Topical review electromagnetically induced
	  transparency},
	journal     = {J. Mod. Opt.},
	year	    = {1998},
	volume	    = {45},
	pages	    = {471-503},
	abstract    = {The subject of electromagnetically induced
	  transparency (EIT) is reviewed in this paper. Emphasis is placed on
	  the experimental work reported in this field since 1990.
	  Theoretical work is also covered, although it is not intended to
	  review all the very numerous recent theoretical treatments on this
	  topic. The basic physical ideas behind EIT are elucidated. The
	  relation of EIT to other processes involving laser-induced atomic
	  coherence, such as coherent population trapping, coherent adiabatic
	  population transfer and lasing without inversion, is discussed.
	  Experimental work is described covering the following topics: EIT
	  with pulsed and continuouswave sources, lasing without inversion,
	  pulse propagation in a laser dressed medium and EIT in nonlinear
	  optical processes. A full set of references and a bibliography are
	  included.}
}

@ARTICLE{LukinFSV98,
	author	    = {Lukin, M. D. and Fleischhauer, M. and Scully, M. O.
	  and Velichansky, V. L.},
	title	    = {Intracavity electromagnetically induced transparency},
	journal     = {Opt. Lett.},
	year	    = {1998},
	volume	    = {23},
	pages	    = {295-297},
	abstract    = {The effect of intracavity electromagnetically induced
	  transparency (EIT) on the properties of optical resonators and
	  active laser devices is discussed theoretically. Pronounced
	  frequency pulling and cavity-linewidth narrowing are predicted. The
	  EIT effect can be used to reduce classical and quantumphase noise
	  of the beat note of an optical oscillator substantially.
	  Fundamental limits of this stabilization mechanism as well as its
	  potential application to high- resolution spectroscopy are
	  discussed. (C) 1998 Optical Society of America.
	  }
}

@ARTICLE{VaccaroDRHCH98,
	author	    = {Vaccaro, J. A. and Durrant, A. V. and Richards, D. and
	  Hopkins, S. A. and Chen, H. X. and Hill, K. E.},
	title	    = {Stochastic wavefunction diagrams for
	  electromagnetically induced transparency, inversionless gain and
	  shelving},
	journal     = {J. Mod. Opt.},
	year	    = {1998},
	volume	    = {45},
	pages	    = {315-333},
	abstract    = {A rigorous diagrammatic description of stochastic
	  wavefunction evolution for electromagnetically induced transparency
	  (EIT) and inversionless gain in coherently driven three-level
	  systems is developed and applied to transient and steady-state
	  conditions. Wavefunction trajectories are illustrated for cases
	  that include Lambda and V-type EIT, shelving and dressed-state
	  resonances.
	  }
}

@ARTICLE{ScullyBRZ97,
	author	    = {Scully, M. O. and Bednar, C. J. and Rostovtsev, Y. and
	  Zhu, S. Y.},
	title	    = {Counter-counter-intuitive quantum coherence effects},
	journal     = {Philos. Trans. R. Soc. Lond. Ser. A-Math. Phys. Eng.
	  Sci.},
	year	    = {1997},
	volume	    = {355},
	pages	    = {2305-2311},
	abstract    = {The study of an ensemble of phase-coherent atoms has
	  recently lead to interesting theoretical innovations and
	  experimental demonstrations of counter-intuitive effects such as
	  electromagnetically induced transparency (EIT), lasing without
	  inversion (LWI), enhancement of index of refraction and ultra-
	  large nonlinear susceptibility. In the present notes, we report a
	  couple of new effects along these lines. In fact, it would be fair
	  to call them surprises even in the repertoire of 'counter-
	  intuitive effects', i.e. 'counter-counter-intuitive effects'.
	  Specifically, we will show that the LWI concept, which is based on
	  quantum coherence, has an interesting counterpart in the classical
	  physics of free electron laser operation. In other current work, we
	  find that it is possible to 'lock' atoms in an excited state via
	  atomic coherence. It is, by now, not surprising that such a
	  phase-coherent ensemble can show holes or dark lines in the
	  emission spectrum. It is surprising that we can lock atoms in an
	  excited (normally decaying) state via atomic coherence and
	  interference. Such a phase-coherent collection of atoms, i.e.
	  'phaseonium', is indeed a novel new state of matter.
	  }
}

@ARTICLE{HamHS97,
	author	    = {Ham, B. S. and Hemmer, P. R. and Shahriar, M. S.},
	title	    = {Efficient electromagnetically induced transparency in
	  a rareearth doped crystal},
	journal     = {Opt. Commun.},
	year	    = {1997},
	volume	    = {144},
	pages	    = {227-230},
	abstract    = {We have observed up to 100\% transmission of a probe
	  field at line center due to electromagnetically induced
	  transparency (EIT) in an optically dense rare-earth crystal of Pr3+
	  doped Y2SiO5 at 5.5 K. We also have examined both laser field
	  intensity and temperature dependence of the EIT. Efficient EIT in
	  this crystal opens potential applications such as efficient
	  high-resolution image processing and signal processing, and optical
	  data storage as well as lasers without population inversion in
	  solids. (C) 1997 Elsevier Science B.V.
	  }
}

@ARTICLE{CataliottiFPI97,
	author	    = {Cataliotti, F. S. and Fort, C. and Prevedelli, M. and
	  Inguscio, M.},
	title	    = {Full resolution of the Autler-Townes Zeeman multiplet
	  for cold cesium atoms in a three-level Lambda-type configuration},
	journal     = {Can. J. Phys.},
	year	    = {1997},
	volume	    = {75},
	pages	    = {767-773},
	abstract    = {Cold cesium atoms released from a magneto-optical trap
	  were investigated in Lambda-type configurations of hyperfine levels
	  of the D-2 line. Electromagnetically induced transparency (EIT) was
	  observed and studied as a function of relevant parameters of the
	  pump-probe lasers. Full resolution of the Zeeman degeneracy was
	  obtained for the first time through the different dependence of the
	  Autler-Townes effect.
	  }
}

@ARTICLE{LukinFZRVHS97,
	author	    = {Lukin, M. D. and Fleischhauer, M. and Zibrov, A. S.
	  and Robinson, H. G. and Velichansky, V. L. and Hollberg, L. and
	  Scully, M. O.},
	title	    = {Spectroscopy in dense coherent media: Line narrowing
	  and interference effects},
	journal     = {Phys. Rev. Lett.},
	year	    = {1997},
	volume	    = {79},
	pages	    = {2959-2962},
	abstract    = {Spectroscopic properties of coherently prepared,
	  optically dense atomic media are studied experimentally and
	  analyzed theoretically. It is shown that in such media the power
	  broadening of the resonances can be substantially reduced. A
	  density-dependent spectral narrowing of the electromagnetically
	  induced transparency (EIT) window and novel, even narrower,
	  resonances superimposed on the EIT line are observed in dense Rb
	  vapor. A nonlinear two-photon spectroscopic technique based on
	  coherent atomic media and combining high resolution with a large
	  signal-to-noise ratio seems feasible.
	  }
}

@ARTICLE{Kofman97,
	author	    = {Kofman, A. G.},
	title	    = {Electromagnetically induced transparency with coherent
	  and stochastic fields},
	journal     = {Phys. Rev. A},
	year	    = {1997},
	volume	    = {56},
	pages	    = {2280-2291},
	abstract    = {This paper deals with electromagnetically induced
	  transparency (EIT), i.e., a significant suppression of absorption
	  at a material transition (in the form of a dip in an absorption
	  spectrum), due to a strong laser field, coupling the excited level
	  with an auxiliary excited (unpopulated) level. A comprehensive
	  theory of EIT is developed for the cases of coherent and Markovian
	  phase-and amplitude-phase-fluctuating coupling fields. For a
	  coherent coupling field, a shift of the absorption minimum from the
	  two-photon resonance is revealed in the off-resonance case. Two
	  models of amplitude-phase fluctuating fields are considered: the
	  chaotic field and the uncorrelated-jump field. Closed analytical
	  expressions for EIT line shape are derived and exact Limits of
	  different regimes of EIT an obtained, the emphasis being on the
	  near-resonance case, The main conclusion is that an
	  amplitude-phase-fluctuating field can induce significant
	  transparency, though reduced in comparison to a phase-fluctuating
	  field of the same average intensity and bandwidth. EIT decreases
	  with the increase of the bandwidth for all stochastic models
	  considered. EIT with a chaotic field is generally less pronounced
	  than EIT with an uncorrelated-jump field of the same intensity and
	  bandwidth, the difference increasing with the field intensity. The
	  possibility of experimental verification of the results obtained is
	  discussed.
	  }
}

@ARTICLE{HamSH97,
	author	    = {Ham, B. S. and Shahriar, M. S. and Hemmer, P. R.},
	title	    = {Enhanced nondegenerate four-wave mixing owing to
	  electromagnetically induced transparency in a spectral holeburning
	  crystal},
	journal     = {Opt. Lett.},
	year	    = {1997},
	volume	    = {22},
	pages	    = {1138-1140},
	abstract    = {We have demonstrated electromagnetically induced
	  transparency (EIT) in an inhomogeneously broadened spectral
	  hole-burning system of Pr3+-doped Y2SiO5 at 6 K. We have also shown
	  enhancement of four-wave mixing under conditions of reduced
	  absorption. This demonstration opens the possibilities of pursuing
	  EIT applications such as high-resolution optical image processing
	  and optical data storage in solids. (C) 1997 Optical Society of
	  America.
	  }
}

@ARTICLE{ZhangTSH97,
	author	    = {Zhang, G. Z. and Tokaryk, D. W. and Stoicheff, B. P.
	  and Hakuta, K.},
	title	    = {Nonlinear generation of extreme-ultraviolet radiation
	  in atomic hydrogen using electromagnetically induced transparency},
	journal     = {Phys. Rev. A},
	year	    = {1997},
	volume	    = {56},
	pages	    = {813-819},
	abstract    = {Sum-frequency generation enhanced by
	  electromagnetically induced transparency (EIT) has been extended to
	  the production of extreme ultraviolet (XUV) radiation in the range
	  97.3-92.6 nm from np-ls transitions (n = 4-8) in atomic hydrogen.
	  Pulsed radiation Was generated by strong coupling of the np and 2s
	  levels with laser radiation at Balmer wavelengths, and
	  simultaneously (weaker) coupling of the 2s and Is levels by
	  two-photon resonance with 243-nm laser radiation.
	  Investigations were carried out over a range of laser intensities
	  and products of interaction length and atomic density (NL). As the
	  product NL increased, the XUV intensities were greatly enhanced by
	  EIT, and at high NL values, the spectral distributions of some of
	  the generated signals were found to be distorted by the presence of
	  molecular hydrogen. Calculated profiles, modified to incorporate
	  the effects of nearby molecular resonances, were shown to be in
	  good agreement with the observed spectra.
	  }
}

@ARTICLE{SchmidtCGI97,
	author	    = {Schmidt, H. and Campman, K. L. and Gossard, A. C. and
	  Imamoglu, A.},
	title	    = {Tunneling induced transparency: Fano interference in
	  intersubband transitions},
	journal     = {Appl. Phys. Lett.},
	year	    = {1997},
	volume	    = {70},
	pages	    = {3455-3457},
	abstract    = {We report the observation of tunneling induced
	  transparency in asymmetric double quantum well structures. Resonant
	  tunneling through a thin barrier is used to coherently couple the
	  two upper states in a three level system of electronic subbands in
	  a GaAs/AlGaAs structure. This creates Fano-type interferences for
	  the collective intersubband excitations in the absorption from the
	  ground state, analogous to electromagnetically induced transparency
	  (EIT) in atomic systems. We observe a 50\% reduction in absorption
	  between the subband resonances which can be explained by taking
	  into account the coherent coupling of the upper states. We analyze
	  the bias dependent absorption spectra and determine the relevant
	  lifetime broadening and dephasing rates for the transitions. (C)
	  1997 American Institute of Physics.
	  }
}

@ARTICLE{FortCHIP97,
	author	    = {Fort, C. and Cataliotti, F. S. and Hansch, T. W. and
	  Inguscio, M. and Prevedelli, M.},
	title	    = {Gain without inversion on the cesium D-1 line},
	journal     = {Opt. Commun.},
	year	    = {1997},
	volume	    = {139},
	pages	    = {31-34},
	abstract    = {We investigated electromagnetically induced
	  transparency (EIT) in a V-type system in cesium at room
	  temperature: a strong coupling laser at 852 nm was locked on the
	  D-2 transition while the transmission of a weak probe at 894 nm has
	  been recorded as the frequency was scanned through the D-1
	  transition. The addition of an incoherent pump on the D-1 line has
	  allowed for the observation of non-inverted gain. A systematic
	  investigation of the effect for different hyperfine sublevels has
	  been performed as a function of the relevant experimental
	  parameters.
	  }
}

@ARTICLE{HopkinsUCD97,
	author	    = {Hopkins, S. A. and Usadi, E. and Chen, H. X. and
	  Durrant, A. V.},
	title	    = {Electromagnetically induced transparency of
	  laser-cooled rubidium atoms in three-level Lambda-type systems},
	journal     = {Opt. Commun.},
	year	    = {1997},
	volume	    = {138},
	pages	    = {185-192},
	abstract    = {We have observed electromagnetically induced
	  transparency (EIT) in laser-cooled rubidium in a magneto-optical
	  trap (MOT). Lambda-type configurations of hyperfine levels of the
	  D2 line were studied, as well as a system utilising degenerate
	  Zeeman sublevels of the ground state. V-type signals were also
	  seen. The perturbing effects of the MOT were found to be small and
	  the results agree well with standard EIT theory for
	  homogeneously-broadened samples.
	  }
}

@ARTICLE{SandhyaS97,
	author	    = {Sandhya, S. N. and Sharma, K. K.},
	title	    = {Atomic coherence effects in four-level systems:
	  Doppler-free absorption within an
	  electromagnetically-induced-transparency window},
	journal     = {Phys. Rev. A},
	year	    = {1997},
	volume	    = {55},
	pages	    = {2155-2158},
	abstract    = {We report here an effect in a four-level ladderlike
	  system, which is in contrast to the usual quantum interference
	  effects such as electromagnetically induced transperency (EIT) or
	  coherent population trapping: we predict the occurrence of a narrow
	  absorption peak within the EIT window when an EIT atomic system
	  interacts with an additional driving rf field. The
	  Doppler-free-central absorption appears when the three-photon
	  resonance condition is satisfied. In the limit of the rf field
	  strength Omega(rf)-->0, the usual EIT profile is recovered.}
}

@ARTICLE{GongXP97,
	author	    = {Gong, S. Q. and Xu, Z. Z. and Pan, S. H.},
	title	    = {Electromagnetically induced focusing in a Lambda-type
	  medium},
	journal     = {Acta Phys. Sin.-Overseas Ed.},
	year	    = {1997},
	volume	    = {6},
	pages	    = {13-17},
	abstract    = {Electromagnetically induced transparency (EIT) in an
	  inhomogenously broadened medium consisting of h-type threelevel
	  atoms has been analyzed. It is shown that the Lambda system can
	  induce a transparency of the medium when the probe laser and the
	  coupling laser have the same frequency detunings (including zero).
	  Across the EIT window, the radial variation of the strong coupling
	  laser radiation may lead to electromagnetically induced focusing or
	  defocusing of the weak probe laser at separate probe frequency
	  detuning points.}
}

@ARTICLE{ShepherdFD96,
	author	    = {Shepherd, S. and Fulton, D. J. and Dunn, M. H.},
	title	    = {Wavelength dependence of coherently induced
	  transparency in a Doppler-broadened cascade medium},
	journal     = {Phys. Rev. A},
	year	    = {1996},
	volume	    = {54},
	pages	    = {5394-5399},
	abstract    = {The effect of changing the coupling laser transition,
	  and hence the wavelength, on the coherently induced transparency
	  seen by a probe beam in a Doppler-broadened cascade
	  electromagnetically induced transparency (EIT) configuration is
	  studied experimentally and theoretically. The transparency of the
	  vapor is shown to be an effect not just of EIT, but of the varying
	  Autler-Townes splitting for each velocity group within the vapor.
	  Consequently, the best overall transparency for Rabi splittings
	  less than the Doppler width is not at the position of matched
	  coupling and probe wavelengths, but for coupling wavelengths less
	  than that of the probe.
	  }
}

@ARTICLE{LiX96,
	author	    = {Li, Y. Q. and Xiao, M.},
	title	    = {Enhancement of nondegenerate four-wave mixing based on
	  electromagnetically induced transparency in rubidium atoms},
	journal     = {Opt. Lett.},
	year	    = {1996},
	volume	    = {21},
	pages	    = {1064-1066},
	abstract    = {We report an experimental observation of the
	  enhancement of nondegenerate four-wave mixing (NDFWM) based on
	  electromagnetically induced transparency (EIT) in a lambda-type
	  three-level system of rubidium atoms. We measured both the linear
	  susceptibility Im chi(1) over (D) (absorption) and the third-order
	  nonlinear coefficient chi(3) over (D) separately for the NDFWM
	  process at a low atomic density. We found that, owing to the EIT
	  effect, the linear absorption term Im chi(1) over d(D) is greatly
	  reduced, while the nonlinear generation term chi(3) over (D) is
	  resonantly enhanced, permitting us to observe a significant
	  enhancement of the NDFWM signal in an optically dense medium. (C)
	  1996 Optical Society of America.}
}

@ARTICLE{RiceB96,
	author	    = {Rice, P. R. and Brecha, R. J.},
	title	    = {Cavity induced transparency},
	journal     = {Opt. Commun.},
	year	    = {1996},
	volume	    = {126},
	pages	    = {230-235},
	abstract    = {We consider a two-level atom inside a cavity. We find
	  that the absorption spectrum of the atom may exhibit a hole at line
	  center for a weak probe. This hole appears when the cavity
	  linewidth is small compared to the atom-field coupling strength,
	  which is itself smaller than the atom's free space linewidth. In
	  the weak-field limit, this system is analogous to a three-level
	  atom, where similar absorption holes at line center occur due to
	  electromagnetically induced transparency (EIT). In EIT, a strong
	  field is required to strongly mix the upper two levels, whereas in
	  the system we consider, it is the atom-field coupling strength that
	  plays this role. An alternate explanation in terms of interference
	  between the cavity field and atomic polarization is given. We also
	  examine the driven cavity case.
	  }
}

@ARTICLE{MoseleySFSD96,
	author	    = {Moseley, R. R. and Shepherd, S. and Fulton, D. J. and
	  Sinclair, B. D. and Dunn, M. H.},
	title	    = {Electromagnetically-induced focusing},
	journal     = {Phys. Rev. A},
	year	    = {1996},
	volume	    = {53},
	pages	    = {408-415},
	abstract    = {The theoretical basis for electromagnetically-induced
	  focusing (EIF), which is caused by spatial variations-in the
	  coupling laser strength in an electromagnetically-induced
	  transparency (EIT) experiment, is studied in detail. Using a
	  numerical model it is shown that radial changes in both absorption
	  and refractive index are important in predicting the probe beam's
	  propagation conditions. Detailed calculations of the focusing and
	  defocusing during EIF under various conditions are presented and
	  compared with appropriate experiments.
	  Diffraction like patterns are predicted for, and observed on, a
	  probe beam after propagation through a smaller EIT aperture.}
}

@ARTICLE{FultonSMSD95,
	author	    = {Fulton, D. J. and Shepherd, S. and Moseley, R. R. and
	  Sinclair, B. D. and Dunn, M. H.},
	title	    = {Continuous-wave electromagnetically induced
	  transparency - a comparison of v-system, lambda-system, and cascade
	  systems},
	journal     = {Phys. Rev. A},
	year	    = {1995},
	volume	    = {52},
	pages	    = {2302-2311},
	abstract    = {A theoretical and experimental investigation has been
	  carried out into the viability of V-type, Lambda-type, and cascade
	  systems within rubidium for the observation of
	  electromagnetically-induced transparency (EIT), A Lambda-type
	  system is also discussed where EIT is induced on a two-photon
	  transition. Continuous-wave single-frequency titanium sapphire
	  lasers have been employed to provide the applied optical fields. It
	  is found that systems that have a strong coupling field resonant
	  with the 5S(1/2) ground state suffer from complicating optical
	  pumping mechanisms that tend to mask EIT windows. It is also found
	  that wavelength matching of the applied optical fields enhances the
	  observation of EIT since this results in a reduced residual Doppler
	  linewidth of the atomic system.
	  }
}

@ARTICLE{MoseleySFSD95,
	author	    = {Moseley, R. R. and Shepherd, S. and Fulton, D. J. and
	  Sinclair, B. D. and Dunn, M. H.},
	title	    = {2-photon effects in continuous-wave
	  electromagnetically-induced transparency},
	journal     = {Opt. Commun.},
	year	    = {1995},
	volume	    = {119},
	pages	    = {61-68},
	abstract    = {Electromagnetically-induced transparency (EIT) in a
	  cascade three-level scheme is studied in rubidium vapour using
	  continuous-wave titanium sapphire lasers. A counter-propagating
	  experimental configuration significantly reduces the coupling laser
	  power requirements and a reduction in absorption of over 90\% is
	  observed. The hyperfine structure of the upper level is seen within
	  the EIT feature and the application of EIT to highresolution
	  two-photon spectroscopy is discussed. Simultaneous measurements of
	  the excitation to the upper state are presented and clearly show
	  Autler-Townes splitting and power broadening.}
}