I have made the numerical core of fresnel.li publicly available on GitHub.
Fresnelli is a C++ program for calculating near-field diffraction patterns of complex apertures using an FFT-based implementation of the Rayleigh–Sommerfeld diffraction integral. The input field, propagation parameters, wavelength, sampling, and output file are defined through a simple configuration file.
The source code and documentation are available on GitHub, while precompiled Windows binaries can be downloaded here:
- Windows binary: Download Fresnelli
- Source code: View on GitHub
- Online version: fresnel.li
The program is based on the method described by R. S. Bennink, A. K. Powell, and D. A. Fish in An efficient method of implementing near-field diffraction in computer-generated hologram design.