Photorefractive crystal-based IR optical modulation
Chii-Maw Uang, Weifeng Lin · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
An Infrared optical modulation (reticle or chopper) is used to provide directional information of infrared system for tracking and to suppress the unwanted signals from backgrounds. In this paper an infrared optical modulation using Photorefractive crystal associative memory (PRAM) technique will be provided. The proposed PRAM is used to replace the optical modulator (reticle) by using an associative hologram technique. The hologram is insert in the optical path between the optical lens of the optical system and the detector in the focal plane of the lens. When the IR fluxes illuminate the hologram, the hologram redirects the flux to the desired direction. A particular arranged detector generating the codes correspond to its position. By use of the optical signal processing and neuron network theorem, the background radiation of IR system can be suppressed effectively. Computer simulation results of PRAM based IR optical modulation are shown to be consistent with the theoretical analysis.