Dye-doped liquid crystal composite for real-time holography

Abstract

In this paper we report the results of dynamic phase grating formation in an anthraquinone derivative dichroic dye-doped nematic liquid crystal in which an external DC electric field was used to change the planar alignment of liquid crystal molecules into a near homeotropic one. This field was also needed to produce an efficient grating via photoconductivity-induced molecular reorientation in a degenerate two-wave mixing experiment with He - Ne (632.8 nm) laser light serving as a low power excitation source. The characteristic of the measured effect shows that the mechanism of grating formation is evidently a non-photorefractive one. A diffraction efficiency of up to 20% has been measured in the system. Fast hologram recording and erasing times (1 ms) make this system attractive for image processing applications.