Photorefractive temporal frequency band-pass band-reject and high-pass optical spatial filters using Michelson interferometry

摘要

Full optical implementation of band-pass, band-reject and high-pass temporal frequency spatial filters for amplitude images are proposed. These filters rely on the exponential temporal response of photorefractive crystals and the interference with phase conjugate beams. Band-pass and high-pass filters may be realized using a phase conjugate Michelson interferometer which has a difference in the response times between two arms, and band-reject filter using the interference between the output from a band-pass filter and a reference beam. The frequency characteristics of these filters are analyzed with numerical examples, and an analogy of these optical filters to corresponding electronic circuits is introduced.