Adding a script that plots images OD images from the raw hdf5 files and a script to carry out some calculations for the Accordion Lattice.

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Karthik 2024-09-17 20:13:52 +02:00
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%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*1.660539066E-27;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*9.274009994E-24;
%% Lattice spacing
Wavelength = 532e-9;
theta = linspace(1.5, 18.0, 100);
LatticeSpacing = Wavelength ./ (2.*sin((theta*pi/180)/2));
figure(1);
set(gcf,'Position',[100 100 950 750])
plot(theta, LatticeSpacing * 1E6, LineWidth=2.0)
xlim([0 19]);
ylim([0.5 21]);
xlabel('Angle (deg)', FontSize=16)
ylabel('Lattice spacing (µm)', FontSize=16)
title(['\bf Upper bound = ' num2str(round(max(LatticeSpacing * 1E6),1)) ' µm ; \bf Lower bound = ' num2str(round(min(LatticeSpacing * 1E6),1)) ' µm'], FontSize=16)
grid on
%% Scaling of vertical trap frequency with lattice spacing
Wavelength = 532e-9;
a = 180 * (AtomicUnitOfPolarizability / (2 * SpeedOfLight * VacuumPermittivity));
Power = 5;
waist_y = 250E-6;
waist_z = 50E-6;
TrapDepth = ((8 * a * Power) / (pi * waist_y * waist_z)) / (BoltzmannConstant * 1E-6); % in µK
thetas = linspace(1.5, 18.0, 100);
LatticeSpacings = zeros(1, length(thetas));
Omega_z = zeros(1, length(thetas));
for idx = 1:length(thetas)
theta = 0.5 * thetas(idx) .* pi/180;
LatticeSpacings(idx) = Wavelength ./ (2.*sin(theta));
Omega_z(idx) = sqrt(((16 * a * Power) / (pi * Dy164Mass * waist_y * waist_z)) * ...
((2 * (cos(theta)/waist_z)^2) + ((Wavelength * sin(theta)/pi)^2 * ...
((1/waist_y^4) + (1/waist_z^4))) + (pi / LatticeSpacings(idx))^2));
end
nu_z = Omega_z ./ (2*pi);
figure(2);
set(gcf,'Position',[100 100 950 750])
plot(LatticeSpacings * 1E6, nu_z * 1E-3, LineWidth=2.0)
xlim([0.5 21]);
xlabel('Lattice spacing (µm)', FontSize=16)
ylabel('Trap frequency (kHz)', FontSize=16)
title(['\bf Upper bound = ' num2str(round(max(nu_z * 1E-3),2)) ' kHz ; \bf Lower bound = ' num2str(round(min(nu_z * 1E-3),2)) ' kHz'], FontSize=16)
grid on
%% Scaling of Recoil Energy - All energy scales in an optical lattice are naturally parametrized by the lattice recoil energy
LatticeSpacing = linspace(2E-6, 20E-6, 100);
RecoilEnergy = PlanckConstant^2 ./ (8 .* Dy164Mass .* LatticeSpacing.^2);
figure(3);
set(gcf,'Position',[100 100 950 750])
semilogy(LatticeSpacing * 1E6, RecoilEnergy/PlanckConstant, LineWidth=2.0, DisplayName=['\bf Max = ' num2str(round(max(RecoilEnergy / PlanckConstant),1)) ' Hz; Min = ' num2str(round(min(RecoilEnergy / PlanckConstant),1)) ' Hz'])
xlim([0.5 21]);
xlabel('Lattice spacing (µm)', FontSize=16)
ylabel('Recoil Energy (Hz)', FontSize=16)
title('\bf Scaling of Recoil Energy - All energy scales in an optical lattice are naturally parametrized by the lattice recoil energy', FontSize=12)
grid on
legend(FontSize=12)
%% Interference pattern spacing in ToF - de Broglie wavelength associated with the relative motion of atoms
ExpansionTime = linspace(1E-3, 20.0E-3, 100);
figure(4);
set(gcf,'Position',[100 100 950 750])
labels = [];
for ls = [2E-6:2E-6:5E-6 6E-6:6E-6:20E-6]
InteferencePatternSpacing = (PlanckConstant .* ExpansionTime) ./ (Dy164Mass * ls);
plot(ExpansionTime*1E3, InteferencePatternSpacing* 1E6, LineWidth=2.0, DisplayName=['\bf Lattice spacing = ' num2str(round(max(ls * 1E6),1)) ' µm'])
hold on
end
xlim([0 22]);
xlabel('Free expansion time (milliseconds)', FontSize=16)
ylabel('Interference pattern period (µm)', FontSize=16)
title('\bf Interference of condensates - Fringe period is the de Broglie wavelength associated with the relative motion of atoms', FontSize=12)
legend(labels, 'Location','NorthWest', FontSize=12);
grid on
legend show

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%% Parameters
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", "/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", "/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "C:/Users/Karthik/Documents/GitRepositories/Calculations/24/";
run = '0086';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 90;
center = [2100, 1150];
span = [500, 500];
fraction = [0.1, 0.1];
pixel_size = 4.6e-6;
%% Compute OD image, rotate and extract ROI for analysis
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = im2double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = im2double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = im2double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
refimages(:,:,k) = subtract_offset(crop_image(bkg_img, center, span), fraction);
absimages(:,:,k) = subtract_offset(crop_image(calculate_OD(atm_img, bkg_img, dark_img), center, span), fraction);
end
%% Fringe removal
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
%%
figure(1)
clf
r = 120;
x = 250;
y = 250;
for k = 1 : length(od_imgs)
imagesc(xvals, yvals, od_imgs{k})
hold on
th = 0:pi/50:2*pi;
xunit = r * cos(th) + x;
yunit = r * sin(th) + y;
h = plot(xunit, yunit, Color='yellow');
xlabel('µm', 'FontSize', 16)
ylabel('µm', 'FontSize', 16)
axis equal tight;
hcb = colorbar;
hL = ylabel(hcb, 'Optical Density', 'FontSize', 16);
set(hL,'Rotation',-90);
colormap jet;
set(gca,'CLim',[0 1.0]);
set(gca,'YDir','normal')
title('DMD projection: Circle of radius 200 pixels', 'FontSize', 16);
drawnow;
end
%% Helper Functions
function ret = get_offset_from_corner(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtract_offset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = get_offset_from_corner(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = crop_image(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function ret = calculate_OD(imageAtom, imageBackground, imageDark)
% Calculate the OD image for absorption imaging.
% :param imageAtom: The image with atoms
% :type imageAtom: numpy array
% :param imageBackground: The image without atoms
% :type imageBackground: numpy array
% :param imageDark: The image without light
% :type imageDark: numpy array
% :return: The OD images
% :rtype: numpy array
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
ret = -log(double(abs(denominator ./ numerator)));
if numel(ret) == 1
ret = ret(1);
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end