Author: Svetlin V. Tassev (Braintree High School, Harvard-Smithsonian Center for Astrophysics)

Initial public release date: Feb 14,2018

pyHoloGen is a multithreaded Python/Cython code for calculating computer-generated binary holograms (CGH).

I wrote the code to produce diffraction demonstrations for my physics classes. Therefore, do not expect the code to be fast. However, I did spend time to optimize the attenuation function (in holo_sum.pyx), so that the holograms that are produced are usable when printed on transparencies with a 1200x600dpi printer: indeed, the quality of the holographic image (especially, when printing at low dpi) can be improved quite a lot by playing with that function. I usually print the holograms, covering the full letter format; thus, one can look through the hologram with both eyes, taking advantage of depth perception. I have also successfully transferred the holograms to slides at resolutions of up to 5000dpi. To do that, I just take a photo with a film camera of the generated hologram image as it is shown on my laptop screen. An ISO-50 black and white film works well. I have included some more suggestions in the code itself.

If you use pyHoloGen for educational purposes or just for fun, I'd appreciate it if you send me a note, example files, video of a hologram in action, etc. I'd be more than happy to add your examples as a resource in the downloads section with proper attribution.

• pyHoloGen is free and open-source software, distributed under the GPLv3 license.

• To build the code, you need to run:

#!bash

  python2 setup.py build_ext --inplace

• To compile successfully, you need to have the following packages installed: Python 2.7, Cython, NumPy, as well as their respective dependencies.

• An example input.dat file is included along with example.py which produces a hologram image file, which is also available in the downloads section. There you can find a video of the hologram in action. The input dat file contains 4 columns: object brightness, x,y,z coordinates in meters. The hologram plane is at z=0. To run the example file just type:

#!bash

  python2 example.py