Genetic optimization of modulation characteristics for two twisted nematicliquid crystal spatial light modulators

A single twisted nematic liquid crystal spatial light modulator may suffer from coupled amplitude modulation and a phase modulation capability of less than 2 pi, although almost all panels can achieve pi. Two twisted nematic liquid crystal panels can be combined in an optical system to produce a tot al phase modulation of at least 2 pi, and a minimal coupled amplitude modul ation. A genetic algorithm is used to optimize the combined modulation char acteristics of two liquid crystal panels in a multiplicative architecture. Simulation results and experimental verification are presented which show a substantial reduction in the combined amplitude modulation, and a total ph ase modulation of 2 pi.