All optical nonlinear joint fourier transform correlator

摘要

A fully parallel, self-aligning, nonlinear and all optical joint transform correlator utilizes a photorefractive four wave mixer positioned to record the joint transform spectrum interfering with a reference beam together with a phase conjugator which directs a readout beam at the four wave mixer. The signal readout of the mixer is Fourier transformed and can be recorded upon an image sensor to detect the correlation spots indicating the degree of similarity of the two input images.