Phase distortion compensation in a joint Fourier transform correlator by phase conjugation

Abstract

In a coherent image processing system, the input object must be free from phase distortion. Unfortunately, most real-time spatial light modulators suffer from phase distortions. Liquid gates can be used to compensate for external distortion but do not remove internal nonuniformities in the devices. Holographic elements can correct phase distortion but require critical alignment. This paper investigates the use of a phase conjugate wave compensating technique to correct for phase distortions in a joint Fourier transform correlator. Because the object beam passes through the objects twice, the contrast of the objects is increased. In the experimental setup, a BSO crystal was utilized as the phase conjugating mirror. The experimental result verified that the phase conjugating technique can compensate for the phase distortion in a joint transform correlator.