Optically Aligned Liquid Crystal Cells as Diffractive Optical Elements

Abstract

Conventional diffractive elements, such as gratings and zone plates, may be regarded as surfaces which are transparent in some regions and opaque in others. Their usefulness stems from the constructive interference of the transmitted light in certain regions of space. Here we propose another way to produce such constructive interference, by allowing light to pass through the originally opaque regions of the diffractive surface but with its polarization rotated by 90°. An interference pattern similar to that of the original surface is obtained, since orthogonal polarizations do not interfere.