Optical correlation via dynamic range compression using organic photorefractive materials

In this paper, we demonstrate optical correlation via dyna mic range compression in two-beam coupling using thin-film organic materials. In contrast to the first demonstration, in which it was not possible to demonstrate correlation with complicated input, here we demonstrate correlation with extremely challenging cases involving finger prints, images in clutter, and SAR images. Our correlation results outperform many correlation results, including ones based on optimal filters. 1. INTRODUCTION In this paper, we demonstrate dynamic range compression co rrelation via a photorefractive two-beam coupling correlator (TBC) which proposed more than a decade ago . 1, 2 The correlator operates by pump ing a clean reference beam by the joint spectra of reference and signal images. The TBC has been studied extensively through computer simulations. In these studies, it was found that, for some cluttered signals, the TBC outperforms, in terms of peak-to noise ratio 2-4 , other correlators based on phase-only filters