Guilin Sun
Ansys Employee
For this term (sqrt(1/uz/k^2)) , I would not write them in this way. uz is the directional cosine, here it is used to correct the intensity cosine decrease, so field correction is inverse sqrt; k should be from Fourier transform. czt does not have any constant in this formula:
but the the Fourier transform has.
In such simulation we do not specify the focal length. Instead, we define the NA of the objective, and suppose "magnification ratio" is unit. if you have other magnification, you will need to modify the code to get enlarged image.
The defocus is used to correct the phase change.

I hope this clarifies them.