Created by sebastien.popoff on 01/10/2021
Spatiotemporal control of lightJoel A. Carpenter Gerchberg-Saxton is a phase retrieval algorithm, which attempts to retrieve the phase corresponding to two intensity images taken in the near and far-field respectively. It can also be used for calculating computer-generated holograms (phase masks) that generate a desired. |
Created by sebastien.popoff on 14/07/2020
Making useless (but beautiful) gifs with fiber modesSocial media like (too) short content like pictures or quotes, but above all, people love gifs (probably way too much). Publish a link to a few pages long post you wrote about a paper, a physical concept, or a piece of code, and a few people will like your tweet/post. Publish a gif, and the number of people you will reach will increase dramatically. Is it a good thing? Well, that depends on what you do with it. I try to use gifs to draw attention to more in-depth content that I hope some people will read. Let's make one together. |
Created by sebastien.popoff on 19/05/2019
Complex-Valued Neural Networks for Physics ApplicationsAn implementation in PyTorch
Artificial neural networks are mainly used for treating data encoded in real values, such as digitized images or sounds. In such systems, using complex-valued tensors would be quite useless. This is however different for physic related topics. When dealing with wave propagation in particular, using complex values is interesting since the physics typically has linear, hence more simple, behavior when considering complex fields. This is sometimes true even when the inputs and the outputs of the system are real values. For instance, consider a complex media that you excite using an amplitude modulator, such as a DMD (Digital Micromirror Device) and you measure the output intensity. You manipulate only real values, but if you want to characterize the system, you have to keep in mind that the phase is a hidden variable as the effect of propagation is represented by the multiplication by a complex matrix on the optical field. |