Optical polarization grating induced liquid crystal micro-structure using azo-dye command layer

Abstract

We create planar-periodic alignment in nematic liquid crystal (LC) cell by using a command layer of azo-dye molecules directly deposited on the cell substrates and exposed with two interfering laser beams of opposite circular polarizations. Permanent high efficiency polarization gratings are thus created. The diffraction efficiency of those gratings is controlled by a uniform electric field applied across the cell. The electro-optical properties of such polarization gratings are studied. Obtained gratings can be used for electrically controlled discrimination and detection of polarized components of light.

Polarization-gratings approach to deformed-helix ferroelectric liquid crystals with subwavelength pitch

“…The holographic technique has been extensively used to create PGs in liquid crystal (LC) cells with photosensitive aligning substrates such as linear photopolymerizable polymer layers [16,17], azo-dye films [18], azo-dye doped polyimide [19,20], and azobenzene side-chain polymer layers [21].…”

Photoaligning and Photopatterning — A New Challenge in Liquid Crystal Photonics

“…Remnant high efficiency polarization gratings were created in nematic liquid crystal cells by layers of azo-dye molecules deposited on the cell substrates and exposed to "interfering" beams with opposite circular polarizations [23]. The diffraction picture was controlled by an electric field applied across the LC cell.…”

Circularly-polarized, large-angle reflective deflectors based on periodically patterned cholesteric liquid crystals

“…However, the angle of de ection was only 0.45°in the previous study, because of limitations in the patterning resolution of helix phase. In this study, we report the fabrication of a large-angle ChLC re ective de ector by performing polarization holography, whereby two orthogonal circularly polarized (CP) beams are superimposed on a photoaligning layer for orientation control [11][12][13][14][15]. Linear polarization gratings with a period as small as 0.84 µm were fabricated, resulting in a di raction angle of 48.9°at a wavelength of 640 nm.…”