Atom L0m cached

1 files changed, 99 insertions, 0 deletions

diff --git a/faraday/susceptibility_problem.m b/faraday/susceptibility_problem.m
new file mode 100644
index 0000000..56808e9
--- /dev/null
+++ b/faraday/susceptibility_problem.m
@@ -0,0 +1,99 @@
+function [xi_linear, xi_left, xi_right]=susceptibility_problem(detuning_freq, Ep, psi_el, B_field, theta, phi) 
+% calculates transmission  if light polarizations  vs B field in the cell
+% for given laser probe and B fields array
+% Probe field defined by field strength (Ep) and ellipticity angle (pse_el)
+% Magnetic field defined by magnitude (B_field) and angles theta and phi. 
+%
+% Note: it is expensive to recalculate atom property for each given B_field strength
+% so run as many calculation for constant magnetic field as possible
+
+t0 = clock (); % we will use this latter to calculate elapsed time
+
+
+% load useful functions;
+useful_functions;
+
+% some physical constants
+useful_constants;
+
+basis_transformation; % load subroutines
+
+
+% load atom energy levels and decay description
+rb87_D1_line;
+
+
+B_str=num2str(B_field(1),"%g");
+% the child  file to which calculated matrices are  written 
+cfile='L0m.cache/L0m_and_polarizability_calculated_for_B=';
+cfile=strcat(cfile,B_str,'.mat');
+
+need_update=true;
+[s, err, msg] = stat (cfile); 
+if(err) 
+	%file does not exist
+	need_update=true; 
+else
+	need_update=false; 
+endif; 
+if ( !need_update)
+		% matrices already calculated and up to date, all we need to load them
+		load(cfile);
+	else
+		% calculate E_field independent properties of the atom
+		% to be used as sub matrix templates for Liouville operator matrix
+		[L0m, polarizability_m]=L0_and_polarization_submatrices( ...
+			Nlevels, ...
+			H0, g_decay, g_dephasing, dipole_elements ...
+		);
+		save(cfile, 'L0m', 'polarizability_m');
+	endif
+
+global atom_properties;
+atom_properties.L0m=L0m;
+atom_properties.polarizability_m=polarizability_m;
+atom_properties.dipole_elements=dipole_elements;
+
+%light_positive_freq  = [wp];
+E_field_drive         = [0    ];
+E_field_probe         = [Ep   ];
+E_field_zero          = [0    ];
+E_field_lab_pos_freq.linear = E_field_zero + (1.00000+0.00000i)*E_field_probe  + (1.00000+0.00000i)*E_field_drive; 
+
+% we define light as linearly polarized 
+% where phi is angle between light polarization and axis x
+% only sign of modulation frequency is important now
+% we define actual frequency later on
+[E_field_lab_pos_freq.x, E_field_lab_pos_freq.y] = rotXpolarization(phi, E_field_lab_pos_freq.linear);
+% we add required ellipticity
+E_field_lab_pos_freq.x*=exp(I*psi_el);
+E_field_lab_pos_freq.y*=exp(-I*psi_el);
+E_field_lab_pos_freq.z=E_field_zero;
+
+E_field_pos_freq=xyz_lin2atomic_axis_polarization(theta, E_field_lab_pos_freq);
+
+
+wp0=w_pf1-w_sf2;  %Fg=2 -> Fe=1
+wp=wp0+detuning_freq;
+light_positive_freq=[ wp];
+% we calculate dc and negative frequencies as well as amplitudes
+[modulation_freq, E_field] = ...
+	light_positive_frequencies_and_amplitudes2full_set_of_modulation_frequencies_and_amlitudes(...
+	light_positive_freq, E_field_pos_freq);
+freq_index=freq2index(wp,modulation_freq);
+
+atom_field_problem.E_field          = E_field;
+atom_field_problem.modulation_freq  = modulation_freq;
+atom_field_problem.freq_index       = freq_index;
+
+problems_cell_array=atom_field_problem;
+
+[xi_linear, xi_left, xi_right]=susceptibility_steady_state_at_freq( problems_cell_array);
+
+
+elapsed_time = etime (clock (), t0)
+return
+
+endfunction
+
+% vim: ts=2:sw=2:fdm=indent