How to plot Fresnel Diffraction?

Question

Mehmet 2014-3-1

评论： Matthew Fisher 2020-12-1

Hi I am trying to plot 1D fresnel diffraction in MATLAB. Is there any way of it?

Image Analyst 2014-3-1

Yes. You need the equation giving the signal as a function of distance, then use plot().

Answer 1

Prasobhkumar P. P. 2020-3-4

编辑：Prasobhkumar P. P. 2020-3-4

function U = fresnel_advance(U0, dx, dy, z, lambda)

% The function receives a field U0 at wavelength lambda

% and returns the field U after distance z, using the Fresnel

% approximation. dx, dy, are spatial resolution.

%If required, Please see below code's 2d version at

k=2*pi/lambda;

[~ nx] = size(U0);

Lx = dx * nx;

dfx = 1./Lx;

u = ones(nx,1)*((1:nx)-nx/2)*dfx;

O = fftshift(fft(U0));

H = exp(1i*k*z).*exp(-1i*pi*lambda*z*(u.^2));

U = ifft2(O.*H);

Matthew Fisher 2020-12-1

Shouldn't H=exp(1i*k*z).*exp(-1i*pi/(lambda*z)*(u.^2))?