Research of the phase-only modulation characterization of a liquid crystal spatial light modulator

LIU Bo-han , ZHANG Jian ,WU Li-ying
(College o f F ine Photoelect ric Instrument and Engineering ,
Harbin Insti tute o f Technology , Harbin 150001 ,China)
Abstract :The principle of phase-only modulation of a liquid crystal spatial lig ht modulator(SLM) was introduced,and it s phase characterist ics were measured by a Twyman-Green interferometer system.The response curves of phase and voltage of the SLM w ith 256*256 pixels patented by Boulder No nlinear Sy stems (BNS) were measured. The program to retrieve the phases  of an arbitrary intensity pattern was developed with an optimal alg orithm. With the phase-only modulation method , the directions and intensities of
laser beams could be controlled by the program easily . An experimental set-up was constructed to generate arbit rary 2-D diffractive pattern with generating pattern time in less than 200ms. This experimental study is of value in the fields of multi-object tracing , laser guiding and multiobject defense.
Key words:spatial light modulato r ;interferome try ;o pt imal alg orithm ;phase modulatio n