Jones-matrix models for twisted-nematic liquid-crystal devices

Twisted-nematic liquid-crystal devices having high spatial resolution are suitable for spatial light modulators. Phase-modulation characteristics of the devices have been widely studied, but the phase delay calculated using a conventional Jones-matrix model is slightly different from that measured using an interferometer. We propose a modified model whose matrix components are described by angular parameters that are related to the distribution of twist and tilt angles inside the liquid-crystal layer through differential equations. The model is used to simulate phase-modulation characteristics, and the result agrees well with the experimentally measured phase delay.