Multilevel anisotropic diffractive optical elements fabricated by means of stepping photo-alignment technique using photo-cross-linkable polymer liquid crystals

Abstract

Multilevel anisotropic diffractive optical elements (DOEs), in which digitized spatial patterns of optical birefringence are fabricated by means of stepping photoalignment technique, has been demonstrated using photo-cross-linkable polymer liquid crystals (PCLCs). The polarization state of incident light is converted into a different polarization state by diffracting light in the practical, i.e., transparent in visible region and thermally stable, multilevel anisotropic DOEs, and both polarization azimuth and ellipticity can be widely controlled by their birefringence patterns. Theoretical considerations for such polarization conversion were also performed using the Jones calculus and diffraction theory and well-explained experimental observations.

Reflectance dependences of diffraction properties in Fabry–Perot liquid crystal polarization grating

“…In this study, although we used the OCPG as the PG, several kinds of other PGs have been reported so far, such as orthogonal linear PG, 10) multilevel anisotropic diffractive films, 12) and crossed-polarization gratings. 11) Therefore, we can fabricate various types of Fabry-Perot PGs showing unique polarization conversion and diffraction properties.…”

“…Moreover, we have also studied LCPGs fabricated using a photo-crosslinkable polymer LC (PCLC). [10][11][12][13] PCLC has the features of high transmittance, high stability against environmental temperature, and high anchoring energy, so we developed several types of LCPG such as crossed polarization gratings, 11) multilevel anisotropic diffractive films, 12) and holographic binary grating LC cells. 13) The advantageous features of these LCPGs have led to applications in optical projection, 14) snapshot-type polarimetry, 15) and optical measurement.…”

Fabrication of Polarization Grating on N-Benzylideneaniline Polymer Liquid Crystal and Control of Diffraction Beam

“…A PG is a diffractive optical element in which the in-plane anisotropic orientation varies linearly along the surface and the magnitude of anisotropy is constant [15][16][17][18][19][20][21][22][23]. It is fabricated by methods such as optical orientation by two-flux interference exposure [24], micro-rubbing [25,26], photomasking [27], and direct beam writing [8,28]. In these methods, the diffraction efficiency is improved by increasing the variation in refractive index in the film or the non-uniform structure of the film.…”

Trifocal lens system with liquid crystal Fresnel lens

“…Owing to these characteristics, LCs have been studied as materials for optical elements such as displays and diffraction gratings. [1][2][3][4][5][6][7][8][9][10] An LC lens is an optical element, and several structures have been proposed thus far for the LC lens. One of the conventional structures contains a Fresnel zone type, in which the LC structure is formed to be mutually aligned to two directions in adjacent zones.…”