<title>Light diffraction on electric-field-induced periodic deformation of the liquid crystal layer</title>

Abstract

The particular diffraction on periodic orientation deformation of liquid crystal (LC) layer was investigated. The deformation was introduced by means of alternative electric field applied across the LC film using electrodes on both substrates plates, or along the one side of the sandwich, using interdigital electrodes patterned on one of the plates. Diffraction pattern was dependent on the frequency and amplitude of driving voltage and the thickness of the LC layer. For the first configuration, diffraction spots correspond to the diffraction period of electrodes. In the second configuration diffraction spots were observed as if the diffraction grating constant is two times smaller. Specific oscillations of intensity with their frequency minimum near 25 and 47 Hz of driving frequency were observed for the spots corresponding to greater period. Achieving this is possible with the increasing driving voltage. The theoretical description of the diffraction process based on earlier results has been shown. Presented formulae illustrate the possibility for twofold deformation maximum appearance in LC layer in dependence of the driving electric field frequency and such parameters as the LC viscosity, and the other mechanisms of dissipation. The computer simulation of the diffraction pattern is made herein.