Diffraction Properties of Nematic Phase Gratings with Photoregulated Liquid Crystal Cells

Abstract

A detailed analysis of the recently proposed [Appl. Phys. Lett. 87 (2005) 161112] nematic phase gratings with photoregulated liquid crystal cells is presented. Nematic phase gratings with photoregulated photo-cross-linkable polymer liquid crystals were prepared and characterized. The phase grating consists of homogeneous and 90 -twisted nematic (TN) areas and shows unique polarization conversion in the diffraction process. The diffraction properties, including higher-ordered diffractions, were well explained by means of the elastic continuum theory, Jones calculus, and diffraction theory.

Alignment structures and diffraction properties of chiral nematic liquid crystal cells with periodically patterned photoalignment films

“…We have studied LC grating cells fabricated using thin films of a photoreactive liquid crystalline polymer (PLCP) with cinnamate side groups. [14][15][16][17][18] In these PLCP films, the side groups of the PLCP were crosslinked by irradiating them with polarized ultraviolet light, and then the molecules were aligned through subsequent annealing at LC temperature. PLCP films with uniaxial alignment are also suitable as alignment layers for LCs with low molecular weight because they are transparent in the visible region and thermally stable, and their anchoring strength is relatively high.…”

“…PLCP films with uniaxial alignment are also suitable as alignment layers for LCs with low molecular weight because they are transparent in the visible region and thermally stable, and their anchoring strength is relatively high. 16) We pre-viously fabricated various grating LC cells by using PLCP films photoregulated by a photomask method, 14,15) polarization holographic recording, 16,18) or polarizer rotation exposure. 17) In these studies, alignment states in the LC cells were observed by polarizing optical microscopy (POM).…”

Liquid Crystal Gratings with Twisted Alignment Produced by One-Step Polarizer-Rotation Exposure on Photocrosslinkable Polymer Liquid Crystal Films

“…29) In addition, the director distribution in the LC grating was estimated based on the elastic continuum theory of nematic LCs, and the diffraction property was theoretically simulated. 30) We proposed a simple yet efficient method to automatically fabricate twisted nematic (TN) structures by one-step exposure on an empty glass cell coated with PCLC films. 31) Since the exposure energy differs with the two PCLC films, due principally to light absorption by the front glass substrate, we were able to obtain TN alignment.…”

Anisotropic Gratings Formed by Photoinduced Molecular Reorientation in Dye-Doped Polymer-Dissolved Liquid Crystal Composites

“…Recently, to fabricate LC gratings, which consist of spatial distributions in a LC molecular orientation, various procedures have been reported. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] Applying a controlled electric field to a LC cell using patterned electrodes is a fundamental method of forming LC gratings. Bos and coworkers investigated the orientation and optical properties of electrically controlled LC gratings, and proposed laser beam steering.…”

“…7,8) Gibbons and Sun demonstrated optically generated LC gratings using photoalignment layers, which were patterned by laser beam drawing 1) In our previous study, LC gratings containing twisted alignments were prepared using liquid crystalline photoalignment layers. 16,17) The layers were photoregulated by photomask exposure. Additionally, Crawford et al prepared LC gratings using photoalignment layers, which were patterned using holographic polarization techniques.…”