Diffraction Efficiency Improvement in Liquid Crystal Blazed Gratings with Spatially Distributed Hybrid Orientation Domains

Diffraction properties of liquid crystal (LC) blazed gratings consisting of spatially distributed hybrid orientation domains were investigated. First, the dependence of diffraction efficiency on cell parameters was clarified; wider grating periods and high blaze levels ensure higher diffraction efficiency. Next, enhancement of the diffraction efficiency of the LC blazed grating was attempted by introducing additional microrubbing patterns. The applicability of the additional pattern for eliminating the disclination was confirmed. It has been revealed that the diffraction efficiency is successfully improved by eliminating the disclination regardless of grating period. The improvement becomes significant for shorter grating periods.