OPTICAL ON-AXIS REAL-TIME PHASE-DOMINANT CORRELATOR USING LIQUID-CRYSTAL TELEVISION

We use a commercially available liquid crystal television (LCTV) for e ncoding the on-axis phase-only filter (POF) in a real-time VanderLugt- type optical correlator. Diffraction theory, computer simulation, and optical experiments show that the coupled amplitude modulation and the phase mismatching in the LCTV yield a zero-order spot in the response of the POF and reduce the diffraction efficiency to about 60 to 70%. The correlation output of the filter is a superposition of the POF cor relation peak and an image of the input. The filter, referred to as th e phase-dominant filter, behaves like the POF with advantages of on-ax is correlation, high light efficiency, and utilization of all the avai lable space bandwidth product of the LCTV. Optical experimental result s are shown.