![]() ![]() %Theory (See also Mar_23.m) % The FT of the 'rect' function is the 'sinc' function. The Finite-Width Single Slit lambda=.633 %Wavelength of laser (micron) =meshgrid((-MeshSize/2:MeshSpacing:MeshSize/2),(-MeshSize/2:MeshSpacing:MeshSize/2)) Ī=RSZ/2)=FGridX_Shift(FGridX_Shift>SZ/2)-SZ įGridY_Shift(FGridY_Shift>SZ/2)=FGridY_Shift(FGridY_Shift>SZ/2)-SZ ![]() MeshSize=200 %Size of Screen (micron) %Calculate and show the Amplitude across the aperture. MeshSpacing=1 %Sampling across aperture (micron) Z=Z_Meters*10^6 %Screen distance in microns Lambda=.633 %Wavelength of laser (micron) The latter function could be sampled with a significantly higher sample width, AR, leading to significant reductions in computer time for the FFT operation. Let's revisit diffraction from a circular aperture. lambda=10 %Try adjusting and look at the result.įigure imshow(abs(F_Wave),) title( '2D FFT of Wave')įigure imshow(abs(F_Wave_Shift),) title( '2D FFT of Wave, DC at Center.') Let's try a simple example to demonstrate the 2D FT. The two dimensional fourier transform is computed using 'fft2'. The complex amplitude at each position can be seen as the 2D Fourier coefficient calculated for the frequency. The complex amplitude of a diffracted wave far from an aperture can be calculated using the Fraunhofer diffraction integral:Īre the coordinates across the aperture, is the complex amplitude across the aperture, and are the coordinates at the screen. Fraunhofer Diffraction and the 2D Fourier Transformįraunhofer Diffraction and the 2D Fourier Transform. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |