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

Abstract

A single twisted nematic liquid crystal spatial light modulator may suffer from coupled amplitude modulation and a phase modulation capability of less than 2π, although almost all panels can achieve π. Two twisted nematic liquid crystal panels can be combined in an optical system to produce a total phase modulation of at least 2π, and a minimal coupled amplitude modulation. A genetic algorithm is used to optimize the combined modulation characteristics 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 phase modulation of 2π.