Scripts for investigating the use of the Sideband Beam to enhance the capture efficiency of the 2-D MOT.

+Scripts/optimizingForSidebandEnhancement.m

@@ -0,0 +1,48 @@
+OptionsStruct = struct;
+OptionsStruct.ErrorEstimationMethod   = 'bootstrap'; % 'jackknife' | 'bootstrap'
+OptionsStruct.NumberOfAtoms           = 5000;
+OptionsStruct.TimeStep                = 50e-06; % in s
+OptionsStruct.SimulationTime          =  4e-03; % in s
+OptionsStruct.SpontaneousEmission     = true;
+OptionsStruct.SidebandBeam            = true;
+OptionsStruct.PushBeam                = true;
+OptionsStruct.Gravity                 = true;
+OptionsStruct.BackgroundCollision     = true;
+OptionsStruct.SaveData                = true;
+% OptionsStruct.SaveDirectory           = '';
+options                               = Helper.convertstruct2cell(OptionsStruct);
+clear OptionsStruct
+
+Oven         = Simulator.Oven(options{:});
+MOT2D        = Simulator.TwoDimensionalMOT(options{:});
+
+%%
+MOT2D.NumberOfAtoms           = 5000;
+MOT2D.TotalPower              = 0.4;
+MOT2D.SidebandBeam            = true;
+NumberOfPointsForFirstParam   = 10; %iterations of the simulation
+NumberOfPointsForSecondParam  = 10;
+DetuningArray                 = linspace(-0.5, -5.0, NumberOfPointsForFirstParam)  * Helper.PhysicsConstants.BlueLinewidth;
+PowerArray                    = linspace(0.1,   1.0, NumberOfPointsForSecondParam) * MOT2D.TotalPower;
+
+tStart = tic;
+[LoadingRateArray, ~, ~]      = Scripts.scanForSidebandEnhancement(Oven, MOT2D, 'Blue', 'BlueSideband', DetuningArray, PowerArray);
+tEnd = toc(tStart);
+fprintf('Total Computational Time: %0.1f seconds. \n', tEnd);
+
+% - Plot results
+
+OptionsStruct = struct;
+OptionsStruct.RescalingFactorForFirstParameter      = (Helper.PhysicsConstants.BlueLinewidth)^-1;
+OptionsStruct.XLabelString                          = 'Sideband Beam Detuning (\Delta/\Gamma)';
+OptionsStruct.RescalingFactorForSecondParameter     = 1000;
+OptionsStruct.YLabelString                          = 'Sideband Beam Power (mW)';
+OptionsStruct.RescalingFactorForQuantityOfInterest  = 1e-9;
+OptionsStruct.ZLabelString                          = 'Loading rate (x 10^{9} atoms/s)';
+OptionsStruct.TitleString                           = sprintf('Magnetic Gradient = %.0f (G/cm)', MOT2D.MagneticGradient * 100);
+
+options                                             = Helper.convertstruct2cell(OptionsStruct);
+
+Plotter.plotResultForTwoParameterScan(DetuningArray, PowerArray, LoadingRateArray, options{:})
+
+clear OptionsStruct

+Scripts/scanForSidebandEnhancement.m

@@ -0,0 +1,33 @@
+function [LoadingRateArray, StandardErrorArray, ConfidenceIntervalArray] = scanForSidebandEnhancement(ovenObj, MOTobj, CBBeamName, SBBeamName, SBDetuningArray, SBPowerArray)
+    
+    Beams                         = MOTobj.Beams;
+    CoolingBeam                   = Beams{cellfun(@(x) strcmpi(x.Alias, CBBeamName), Beams)};                                       
+    SidebandBeam                  = Beams{cellfun(@(x) strcmpi(x.Alias, SBBeamName), Beams)};                                       
+    NumberOfPointsForFirstParam   = length(SBDetuningArray);
+    NumberOfPointsForSecondParam  = length(SBPowerArray);
+    LoadingRateArray              = zeros(NumberOfPointsForFirstParam, NumberOfPointsForSecondParam);
+    StandardErrorArray            = zeros(NumberOfPointsForFirstParam, NumberOfPointsForSecondParam);
+    ConfidenceIntervalArray       = zeros(NumberOfPointsForFirstParam, NumberOfPointsForSecondParam, 2);
+    
+    for i=1:NumberOfPointsForFirstParam
+        eval(sprintf('SidebandBeam.%s = %d;', 'Detuning', SBDetuningArray(i)));
+        for j=1:NumberOfPointsForSecondParam
+            eval(sprintf('SidebandBeam.%s = %d;', 'Power', SBPowerArray(j)));
+            eval(sprintf('CoolingBeam.%s = %d;',  'Power', MOTobj.TotalPower - SBPowerArray(j)));
+            [LoadingRateArray(i,j), StandardErrorArray(i,j), ConfidenceIntervalArray(i,j,:)] = MOTobj.runSimulation(ovenObj);
+        end
+    end
+    
+    if MOTobj.DoSave
+        LoadingRate  = struct;
+        LoadingRate.Values = LoadingRateArray;
+        LoadingRate.Errors = StandardErrorArray;
+        LoadingRate.CI     = ConfidenceIntervalArray;
+        MOTobj.Results = LoadingRate;
+        SaveFolder   = [MOTobj.SaveDirectory filesep 'Results'];
+        Filename     = ['TwoParameterScan_' datestr(now,'yyyymmdd_HHMM')];
+        eval([sprintf('%s_Object', Filename) ' = MOTobj;']);
+        mkdir(SaveFolder);
+        save([SaveFolder filesep Filename], sprintf('%s_Object', Filename));
+    end
+end

+Simulator/@Beams/Beams.m

@@ -5,8 +5,8 @@ classdef Beams < handle & matlab.mixin.Copyable
         BlueBeamDefault         = struct('Alias',                                          'Blue', ...
                                          'Power',                                          400e-3, ...
                                          'Detuning',  -1.39*Helper.PhysicsConstants.BlueLinewidth, ...
-                                         'Radius',                                       16.67e-3, ...
+                                         'Radius',                                          35e-3, ...
-                                         'Waist',                                           15e-3, ...
+                                         'Waist',                                        16.67e-3, ...
                                          'WaveNumber',2*pi/Helper.PhysicsConstants.BlueWavelength, ...
                                          'Linewidth',       Helper.PhysicsConstants.BlueLinewidth, ...
                                          'SaturationIntensity',  0.1 * (2 * pi^2 / 3)    * ...
@@ -17,8 +17,8 @@ classdef Beams < handle & matlab.mixin.Copyable
         BlueSidebandBeamDefault = struct('Alias',                                 'BlueSideband', ...
                                          'Power',                                          200e-3, ...
                                          'Detuning',     -3*Helper.PhysicsConstants.BlueLinewidth, ...
-                                         'Radius',                                       16.67e-3, ...
+                                         'Radius',                                          35e-3, ...
-                                         'Waist',                                           10e-3, ...
+                                         'Waist',                                        16.67e-3, ...
                                          'WaveNumber',2*pi/Helper.PhysicsConstants.BlueWavelength, ...
                                          'Linewidth',       Helper.PhysicsConstants.BlueLinewidth, ...
                                          'SaturationIntensity',  0.1 * (2 * pi^2 / 3)    * ...

+Simulator/@TwoDimensionalMOT/runSimulation.m

@@ -1,11 +1,12 @@
 function [LoadingRate, StandardError, ConfidenceInterval] = runSimulation(this, ovenObj)
-    
+    if this.NumberOfAtoms ~= ovenObj.NumberOfAtoms
+        ovenObj.NumberOfAtoms = this.NumberOfAtoms;
+    end
     %% - Sampling for initial positions and velocities
     % - sampling the position distribution
     Positions  = ovenObj.initialPositionSampling();
     % - sampling the velocity distribution
     Velocities = ovenObj.initialVelocitySampling(this);
-    
     %% Solve ODE 
     progressbar  = Helper.parforNotifications();
     progressbar.PB_start(this.NumberOfAtoms,'Message',['Simulating 2-D MOT capture process for ' num2str(this.NumberOfAtoms,'%.0f') ' atoms:']);

test_MOTCaptureProcessSimulation.m

@@ -7,10 +7,11 @@
 % - Automatically creates Beams objects
 OptionsStruct = struct;
 OptionsStruct.ErrorEstimationMethod   = 'bootstrap'; % 'jackknife' | 'bootstrap'
+OptionsStruct.NumberOfAtoms           = 5000;
 OptionsStruct.TimeStep                = 50e-06; % in s
 OptionsStruct.SimulationTime          =  4e-03; % in s
 OptionsStruct.SpontaneousEmission     = true;
-OptionsStruct.Sideband                = false;
+OptionsStruct.SidebandBeam            = true;
 OptionsStruct.PushBeam                = true;
 OptionsStruct.Gravity                 = true;
 OptionsStruct.BackgroundCollision     = true;
@@ -86,6 +87,7 @@ Plotter.plotPhaseSpaceWithAccelerationField(Oven, MOT2D, MinimumVelocity, Maximu
 
 %% - Plot Trajectories along the 3 directions
 MOT2D.NumberOfAtoms       = 100;
+MOT2D.MagneticGradient    = 0.42;
 MaximumVelocity           = 150;
 IncidentAtomDirection     = 0*2*pi/360;
 IncidentAtomPosition      = 0;