Light Modulator Based on Nematic Liquid Crystal with Super-Twisted Structure Operating in Waveguide Mode with Antisymmetric Boundary Conditions

Abstract

Using the method of computer simulation, the effect of physical constants of a liquid crystalline (LC) material on integral characteristics of a light modulator was studied. The modulator operated in a waveguide mode in the LC structure with a high twist angle and at antisymmetric boundary conditions of the working cell. It was found that the total response time of the LC modulator is inversely proportional to the square of a control voltage and approaches to a certain constant value when the control voltage tends to infinity. The short total response time of the LC modulator with antisymmetric boundary conditions is presumably conditioned by the absence of a “backflow” in the LC cell when the control voltage is removed and by the fact that only half of the working gap thickness effects the switching dynamics. The optimal set of physical parameters of the LC material was deter-mined, at which the contrast ratio is maximal and the total response time of the modulator is minimal. It was es-tablished that each LC material has its own modulator control mode, and the control voltage value and the method of switching between the “on” and “off” states should be selected based on the physical constants of the LC material and the design parameters of the device.