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44 lines
1.4 KiB
Matlab
44 lines
1.4 KiB
Matlab
function [probe] = generate_probe(N, lambda, dx, Ls, setup)
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%UNTITLED Summary of this function goes here
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% Detailed explanation goes here
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%Parameters: N -> number of pixels
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% lambda -> the wave length
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% dx -> pixel size (in sample plane)
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% Ls -> distance from focal plane to sample
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%Fresnel Zone Plate
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switch setup
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case "velo"
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Rn=90e-6;
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dRn=50e-9;
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case "barry"
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Rn=80e-6;
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dRn=70e-9;
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case "barry2"
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Rn=70e-6;
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dRn=160e-9;
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otherwise
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Rn=90e-6;
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dRn=50e-9;
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end
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fl=2*Rn*dRn/lambda;%focal length corresponding to central wavelength
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D_FZP=180e-6;%dimeter of the FZP
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D_H=60e-6;%central beamstop
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%pixel size on FZP plane
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dx_fzp=lambda*fl/N/dx;
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%Coordinate on FZP plane
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lx_fzp=linspace(-dx_fzp*N/2,dx_fzp*N/2,N);
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[x_fzp,y_fzp]=meshgrid(lx_fzp);
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%Transmission function of the FZP
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T=exp(-1j*2*pi/lambda*(x_fzp.^2+y_fzp.^2)/2/fl);
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C=double(sqrt(x_fzp.^2+y_fzp.^2)<=(D_FZP/2));% Cercular function of FZP
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H=double(sqrt(x_fzp.^2+y_fzp.^2)>=(D_H/2));%cental block
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%probe on sample plane
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probe=fresnel_propagation(C.*T.*H,dx_fzp,(fl+Ls),lambda);
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%figure(1);imagesc(abs(probe));axis image
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%figure(2);imagesc(angle(probe));axis image
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end
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