Full-field TN-LCSLM phase modulation characterization using Digital Holography

摘要

A simple, full-field method to characterize phase modulation property of translucent twisted nematic spatial light modulator (TN-LCSLM) is presented using Digital Holography (DH). Generally, amplitude and phase modulation is coupled due to simultaneous distortion in twist alignment and tilt order with applied field. The change in birefringence of liquid crystal material with respect to input grey scale produces phase modulation of wavefront transmitted through TN-LCSLM. Most existing techniques for phase modulation characterization of LCSLM are complex requiring lengthy calculations and measure a very small region of total active region of SLM. In this paper, a transmission Digital Holographic system is used to extract phase information from the digitally recorded and numerically reconstructed wavefront. The advantage of phase modulation characterization using DH is that the phase value from larger area inside the active region of TN-LCSLM can be visualized and quantified in real time.