Holographic Formation of Non-uniform Diffraction Structures by Arbitrary Polarized Recording Beams in Liquid Crystal-photopolymer Compositions

Polymers (Basel). 2019 May 11;11(5):861. doi: 10.3390/polym11050861.

Abstract

In this work, the theoretical model of non-uniform diffraction structures' holographic formation in liquid crystal-photopolymer (LC-PPM) composite materials with a dye-sensitizer is developed. The model takes into account the arbitrary character of amplitude and phase spatial distributions of recording light field, its arbitrary polarization state and also a non-linearity of the recording process. Two the most common types of liquid crystal-photopolymer composite are investigated: Holographic polymer-dispersed liquid crystals (H-PDLC) and polymer-stabilized liquid crystals (PSLC). Numerical simulations for the most common cases of holographic formation schemes are made. It is shown that due to the photo-induced Freedericksz transition, in the case of arbitrary polarization states of recording light beams, the non-uniform polarization diffraction grating (PDG) is formed in LC-PPM. Numerical simulations' results show that PDG's contribution to the change of the dielectric tensor of the media is comparable with the contribution of the photopolymerization-diffusion process.

Keywords: diffraction gratings; holographic polymer-dispersed liquid crystals; holography; polarization diffraction gratings; polymer-stabilized liquid crystals.