Properties of Optically Addressed Liquid Crystal Spatial Light Modulators Studied by Mach-Zehnder Interferometry

摘要

In this work optically addressed liquid crystal spatial light modulators are experimentally investigated. Local reorientation of molecules in the modulator and local changes of effective refractive index n_(eff) (x,y) are induced by modulated light intensity I (x,y). We present preliminary results of measurements of phase shifts in optically addressed liquid crystal panels using a Mach-Zehnder interferometer. Experiments were performed for the panels filled with nematic and dye-doped nematic liquid crystals. Optical addressing was realized by Ar+ laser beam (λ = 514.5 nm) while the reading beam was supplied by He-Ne laser (632.8 nm). The operation voltage was in the range 4 - 20 V. The total phase shift under the influence of addressing light for the studied systems was 2 - 6 π, sensitivity to the addressing light ～ μW/cm~2 per 2π phase change and speed of response to the light was 20 ms - 30 s with total recovery time 0.5 - 120 s.