added draft of squeezing filter

11 files changed, 430 insertions, 0 deletions

diff --git a/squeezing_filter/L0m.cache b/squeezing_filter/L0m.cache
new file mode 120000
index 0000000..c9b0aa9
--- /dev/null
+++ b/squeezing_filter/L0m.cache
@@ -0,0 +1 @@
+../L0m.cache
\ No newline at end of file
diff --git a/squeezing_filter/Makefile b/squeezing_filter/Makefile
new file mode 100644
index 0000000..1121c70
--- /dev/null
+++ b/squeezing_filter/Makefile
@@ -0,0 +1,42 @@
+
+
+PROBLEMS = $(wildcard tasks/*.mat)
+RESULTS = $(PROBLEMS:tasks/%=results/%)
+
+
+calculate: problems  solutions
+
+solutions: results $(RESULTS)
+
+results:
+	@mkdir results
+
+
+problems: tasks problems_prepared.stamp
+
+tasks:
+	@mkdir tasks
+
+problems_prepared.stamp: builder_tasks.m
+	@rm -f tasks/*
+	@./builder_tasks.m
+	@touch $@
+	@echo "Please run again:  make calculate"
+
+$(RESULTS): results/% : tasks/%
+	./solver_task.m $< $@
+
+tasks_clean:
+	rm -rf tasks/*
+
+results_clean:
+	rm -rf results/*
+
+clean: tasks_clean results_clean
+	rm -f problems_prepared.stamp
+	
+
+real_clean: clean
+	rm -rf tasks
+	rm -rf results
+
diff --git a/squeezing_filter/basis_transformation.m b/squeezing_filter/basis_transformation.m
new file mode 120000
index 0000000..28d8beb
--- /dev/null
+++ b/squeezing_filter/basis_transformation.m
@@ -0,0 +1 @@
+../basis_transformation.m
\ No newline at end of file
diff --git a/squeezing_filter/builder_tasks.m b/squeezing_filter/builder_tasks.m
new file mode 100755
index 0000000..970f5e5
--- /dev/null
+++ b/squeezing_filter/builder_tasks.m
@@ -0,0 +1,37 @@
+#!/usr/bin/octave -qf
+
+task_dir='tasks/';
+task_base_name='task_';
+task_ext='.mat';
+data_dir='results/';
+output_dir='results/';
+
+
+detuning_freq_start=-100;
+detuning_freq_stop=-detuning_freq_start;
+
+
+
+% theta is angle between lab z axis (light propagation direction) and magnetic field axis (z')
+theta=0;
+
+Ep=sqrt(0.01);
+Ed=sqrt(100);
+
+% we are going to sweep B so parts related to sweep paramer(s)
+gmg=.7; % gyro magnetic ration for ground level
+zeeman_splitting=+0.5;
+B_field=zeeman_splitting/gmg;
+
+Nsteps=101;
+detunings=linspace(detuning_freq_start, detuning_freq_stop, Nsteps);
+
+for i=1:Nsteps
+	filename_task=strcat(task_dir, task_base_name);
+	i_str=num2str(i, "%04d");
+	filename_task=strcat(filename_task,i_str, task_ext);
+	detuning_freq = detunings(i);
+	save(filename_task, 'detuning_freq', 'Ed', 'Ep', 'B_field', 'theta');
+endfor
+
+disp("Tasks creation done");
diff --git a/squeezing_filter/dipole_elementRb87D1line.m b/squeezing_filter/dipole_elementRb87D1line.m
new file mode 120000
index 0000000..6a11745
--- /dev/null
+++ b/squeezing_filter/dipole_elementRb87D1line.m
@@ -0,0 +1 @@
+../dipole_elementRb87D1line.m
\ No newline at end of file
diff --git a/squeezing_filter/pp_tasks.m b/squeezing_filter/pp_tasks.m
new file mode 100644
index 0000000..a3919ba
--- /dev/null
+++ b/squeezing_filter/pp_tasks.m
@@ -0,0 +1,76 @@
+basis_transformation;
+
+fnames=glob('results/*.mat');
+
+Nsteps=length(fnames)
+B_field=zeros(1,Nsteps);
+xi_linear=zeros(1,Nsteps);
+xi_left=zeros(1,Nsteps);
+xi_right=zeros(1,Nsteps);
+
+% read the information from resulting files
+for i=1:Nsteps
+	d=load(fnames{i});
+	B_field(i)=d.B_field;
+	xi_linear(i)=d.xi_linear;
+	xi_left(i)=d.xi_left;
+	xi_right(i)=d.xi_right;
+	Ep.linear(i)=d.E_field_pos_freq.linear;
+	Ep.left(i)=d.E_field_pos_freq.left;
+	Ep.right(i)=d.E_field_pos_freq.right;
+endfor
+
+Ep_out.linear=(1-xi_linear).*Ep.linear;
+Ep_out.left=(1-xi_left).*Ep.left;
+Ep_out.right=(1-xi_right).*Ep.right;
+
+Ep_out.x= (Ep_out.left + Ep_out.right)/sqrt(2);
+Ep_out.y= 1i*(Ep_out.left - Ep_out.right)/sqrt(2);
+
+xi_x=(xi_right+xi_left)/sqrt(2);
+xi_y=(1i*xi_right-1i*xi_left)/sqrt(2);
+
+%figure(1);
+%plot(B_field, real(xi_x), B_field, real(xi_y));
+%legend('x','y');
+%title('xi-real');
+
+%figure(2);
+%plot(B_field, imag(xi_x), B_field, imag(xi_y));
+%legend('x','y');
+%title('xi-imag');
+
+%figure(3);
+%plot(B_field, real(xi_left), B_field, real(xi_right));
+%legend('left','right');
+%title('xi-real');
+
+%figure(4);
+%plot(B_field, imag(xi_left), B_field, imag(xi_right));
+%legend('left','right');
+%title('xi-imag');
+
+%figure(5);
+%plot(B_field, abs(Ep_out.x).^2, B_field, abs(Ep_out.y).^2 );
+%legend('x','y');
+%title('Signal out');
+
+%figure(6);
+%plot(B_field, abs(Ep_out.left).^2, B_field, abs(Ep_out.right).^2 );
+%legend('left','right');
+%title('Signal out');
+
+figure(7);
+plot(B_field, abs(Ep_out.x).^2 );
+legend('x');
+title('Signal out');
+
+figure(8);
+plot(B_field, abs(Ep_out.y).^2 );
+legend('y');
+title('Signal out');
+
+figure(9);
+plot(B_field, abs(Ep_out.x).^2-abs(Ep_out.y).^2 );
+legend('x-y');
+title('Differential x-y out');
diff --git a/squeezing_filter/rb87_D1_line.m b/squeezing_filter/rb87_D1_line.m
new file mode 100644
index 0000000..74a52f0
--- /dev/null
+++ b/squeezing_filter/rb87_D1_line.m
@@ -0,0 +1,148 @@
+1;
+useful_constants;
+
+% note all frequency values are in MHz
+
+%  87Rb D1 line
+%
+%     m=-2   m=-1   m=0    m=1    m=2
+%     ----   ----   ----   ----   ----   |P,F=2>
+%
+%            ----   ----   ----          |P,F=1>
+%            m=-1   m=0    m=1        
+%
+%
+%
+%
+%
+%     m=-2   m=-1   m=0    m=1    m=2
+%     ----   ----   ----   ----   ----   |S,F=2>
+%
+%            ----   ----   ----          |S,F=1>
+%            m=-1   m=0    m=1        
+
+
+w_hpf_ground=6834;
+w_hpf_exited=817;
+w_sf2 = w_hpf_ground; %            Distance from |S,F=1> to |S,F=2>
+w_pf1       =1e9;  % something big Distance from |S,F=1> to |P,F=1>
+w_pf2       = w_pf1+w_hpf_exited; %Distance from |S,F=1> to |P,F=2> 
+gmg=.7; % gyro magnetic ration for ground level
+gme=.23; % gyro magnetic ration for exited level % CHECKME
+
+
+%bottom level   |F=1>
+levels( 1)=struct( "ang_momentum",  0, "total_momentum",   1, "m",  -1,  "energy",       0, "gm",  -gmg);
+levels( 2)=struct( "ang_momentum",  0, "total_momentum",   1, "m",   0,  "energy",       0, "gm",  -gmg);
+levels( 3)=struct( "ang_momentum",  0, "total_momentum",   1, "m",   1,  "energy",       0, "gm",  -gmg);
+
+%second bottom level |F=2>
+levels( 4)=struct( "ang_momentum",  0, "total_momentum",   2, "m",  -2,  "energy",   w_sf2, "gm",   gmg);
+levels( 5)=struct( "ang_momentum",  0, "total_momentum",   2, "m",  -1,  "energy",   w_sf2, "gm",   gmg);
+levels( 6)=struct( "ang_momentum",  0, "total_momentum",   2, "m",   0,  "energy",   w_sf2, "gm",   gmg);
+levels( 7)=struct( "ang_momentum",  0, "total_momentum",   2, "m",   1,  "energy",   w_sf2, "gm",   gmg);
+levels( 8)=struct( "ang_momentum",  0, "total_momentum",   2, "m",   2,  "energy",   w_sf2, "gm",   gmg);
+
+% first exited level |F=1>
+levels( 9)=struct( "ang_momentum",  1, "total_momentum",   1, "m",  -1,  "energy",   w_pf1, "gm",  -gme);
+levels(10)=struct( "ang_momentum",  1, "total_momentum",   1, "m",   0,  "energy",   w_pf1, "gm",  -gme);
+levels(11)=struct( "ang_momentum",  1, "total_momentum",   1, "m",   1,  "energy",   w_pf1, "gm",  -gme);
+
+% second exited level |F=2>
+levels(12)=struct( "ang_momentum",  1, "total_momentum",   2, "m",  -2,  "energy",   w_pf2, "gm",   gme);
+levels(13)=struct( "ang_momentum",  1, "total_momentum",   2, "m",  -1,  "energy",   w_pf2, "gm",   gme);
+levels(14)=struct( "ang_momentum",  1, "total_momentum",   2, "m",   0,  "energy",   w_pf2, "gm",   gme);
+levels(15)=struct( "ang_momentum",  1, "total_momentum",   2, "m",   1,  "energy",   w_pf2, "gm",   gme);
+levels(16)=struct( "ang_momentum",  1, "total_momentum",   2, "m",   2,  "energy",   w_pf2, "gm",   gme);
+
+Nlevels=size(levels)(2);
+
+
+H0=zeros(Nlevels);
+energy            = [1:Nlevels].*0;
+ang_momentum      = [1:Nlevels].*0;
+total_momentum    = [1:Nlevels].*0;
+m                 = [1:Nlevels].*0;
+gm                = [1:Nlevels].*0;
+
+for i=1:Nlevels
+	energy(i)         = levels(i).energy;
+	ang_momentum(i)   = levels(i).ang_momentum;
+	total_momentum(i) = levels(i).total_momentum;
+	m(i)              = levels(i).m;
+	gm(i)             = levels(i).gm;
+endfor
+H0=diag(energy)*hbar;
+
+
+dipole_elements.left   = zeros(Nlevels);
+dipole_elements.right  = zeros(Nlevels);
+dipole_elements.linear = zeros(Nlevels);
+% define dipole elements for transition from level j->k
+for j=1:Nlevels
+	for k=1:Nlevels
+		if ( abs(ang_momentum(j) - ang_momentum(k)) == 1)
+			%transition allowed for L =L' +/- 1
+			% but they correct within a factor, but not sign
+			if ( ( H0(j,j) < H0(k,k)) )
+				de=dipole_elementRb87D1line(...
+					total_momentum(j),m(j), ...
+					total_momentum(k),m(k)  ...
+				);
+				dipole_elements.left(j,k)   = de.left;
+				dipole_elements.right(j,k)  = de.right;
+				dipole_elements.linear(j,k) = de.linear;
+			endif	
+		endif
+	endfor
+endfor
+dipole_elements.linear+=dipole_elements.linear';
+dipole_elements.left+=dipole_elements.left';
+dipole_elements.right+=dipole_elements.right';
+
+maximum_dipole_elements=abs(dipole_elements.linear) + abs(dipole_elements.left) + abs(dipole_elements.right);
+
+%defasing matrix
+g_deph=0;
+g_dephasing=zeros(Nlevels);
+% dephasing only for non zero dipole elements (am I right?)
+g_dephasing=g_deph*(abs(maximum_dipole_elements) != 0);
+
+% decay matrix g(i,j) correspnds to decay from i-->j
+gamma=6;
+g_decay=zeros(Nlevels);
+for i=1:Nlevels
+	for j=1:Nlevels
+		if (  H0(i,i) > H0(j,j) )
+			% only upper levels decaying and decay is always positive
+			g_decay(i,j)=gamma * abs( maximum_dipole_elements(i,j) );
+		endif
+	endfor
+endfor
+
+% ground level mixing need to be artificial
+gamma_hpf=.0001;
+for i=1:Nlevels
+	for j=1:Nlevels
+		% it would be better to introduce a level corresponding to the bath
+		% but this slows calculations
+		% So 
+		% ground hyperfine are equally mixed together
+		if (  (abs( H0(i,i) - H0(j,j)) == w_hpf_ground*hbar ) || ...
+			    (abs( H0(i,i) - H0(j,j)) == 0 ) )
+			% i and j correspond to 2 ground levels
+			% we cannot decay to itself
+			if ( i != j )	
+				% total eight ground levels F=2 and F=1 so we decay in 7 channels
+				g_decay(i,j)+=gamma_hpf/7; 
+			endif
+		endif
+	endfor
+endfor
+
+% apply B field Zeeman splitting
+energy+=B_field * ( gm .* m);
+% convert frequency to energy units
+H0=diag(energy)*hbar;
+
+% vim: ts=2:sw=2:fdm=indent
diff --git a/squeezing_filter/solver_task.m b/squeezing_filter/solver_task.m
new file mode 100755
index 0000000..1253a6f
--- /dev/null
+++ b/squeezing_filter/solver_task.m
@@ -0,0 +1,20 @@
+#!/usr/bin/octave -qf
+% reads parameters file (argv1)  and output results of the calculations into output file (argv(2)
+
+arg_list = argv ();
+
+if (nargin < 2) 
+	error("need at least two parameters");
+end
+params_file=arg_list{1};
+output_fname=arg_list{2};
+
+load(params_file);
+
+[xi_linear, xi_left, xi_right, E_field_pos_freq, light_positive_freq]=susceptibility_problem(detuning_freq, Ed, Ep, B_field, theta);
+
+save(output_fname, 'detuning_freq', 'Ed', 'Ep', 'B_field', 'theta' ...
+	, 'xi_linear', 'xi_left', 'xi_right' ...
+	, 'E_field_pos_freq', 'light_positive_freq' ...
+	);
+
diff --git a/squeezing_filter/susceptibility_problem.m b/squeezing_filter/susceptibility_problem.m
new file mode 100644
index 0000000..b9c74fc
--- /dev/null
+++ b/squeezing_filter/susceptibility_problem.m
@@ -0,0 +1,102 @@
+function [xi_linear, xi_left, xi_right, E_field_pos_freq, light_positive_freq]=susceptibility_problem(detuning_freq, Ed, Ep, B_field, theta)
+% calculates transmission  if light polarizations  vs B field in the cell
+% for given laser probe, drive  and B field
+% Probe field defined by field strength (Ep), drive (Ed)
+% Magnetic field defined by magnitude (B_field) and angles theta with respect to 'z' axis
+% of light propagation
+%
+% 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;
+
+%wp0=w_pf1-w_sf2;  %Fg=2 -> Fe=1
+w0=w_pf1-w_hpf_exited+w_hpf_exited;  %Fg=2 -> Fe=2
+wp=w0+detuning_freq;
+light_positive_freq=[w0, wp, wp-w0]; % [drive_freq, probe_dreq];
+
+%light_positive_freq  = [wp];
+E_field_drive         = [Ed, 0,  0 ];
+E_field_probe         = [0,  Ep, 0 ];
+E_field_zero          = [0,  0,  0 ];
+E_field_lab_pos_freq.linear = E_field_probe  + 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_drive;
+E_field_lab_pos_freq.y = E_field_probe;
+E_field_lab_pos_freq.z=E_field_zero;
+
+E_field_pos_freq=xyz_lin2atomic_axis_polarization(theta, E_field_lab_pos_freq);
+
+% 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
diff --git a/squeezing_filter/useful_constants.m b/squeezing_filter/useful_constants.m
new file mode 120000
index 0000000..fc5b92d
--- /dev/null
+++ b/squeezing_filter/useful_constants.m
@@ -0,0 +1 @@
+../useful_constants.m
\ No newline at end of file
diff --git a/squeezing_filter/useful_functions.m b/squeezing_filter/useful_functions.m
new file mode 120000
index 0000000..a2d3237
--- /dev/null
+++ b/squeezing_filter/useful_functions.m
@@ -0,0 +1 @@
+../useful_functions.m
\ No newline at end of file