Anisotropic photonic gratings formed in photocross-linkable polymer liquid crystals

Abstract

Large birefringence and polarization holographic gratings formed in photocross-linkable polymer liquid crystals comprising bistolane mesogenic side groupsWe demonstrated anisotropic photonic gratings in photocross-linkable polymer liquid crystals irradiated with three mutually coherent beams. Both birefringence and surface relief modulation were induced by reorientation and/or migration of mesogenic molecules. Anisotropy and optical properties of photonic gratings were strongly dependent on the combination of polarization states of the three beams. Atomic force microscopy revealed that topological patterns of gratings formed according to interference patterns of the three beams and diffraction efficiencies of recorded gratings depended on polarization direction of the linearly polarized probe beam. These diffraction properties including efficiency and optical anisotropy could be explained by the theory based on Jones calculus.

Photoalignment-induced two-dimensional liquid crystal polarization structure via multi-beam polarization interferometry

“…Besides 1D PG based on polarization holography [5][6][7][8][14][15][16], there were several reports about the 2D polarization structure, either by superposition of two 1D polarization patterns [17,18], or through multi-beam interference of LP or CP light [19][20][21]. However, the intensity modulations of the multi-beam polarization holography could cause either topological relief imposed 2D polarization structure of photo-sensitive polymers [19], or non-complete reorientation of the photosensitive material since null intensity areas existed in the interference field [20]. By introducing relative phases into four interferential CP beams, the intensity modulation could be suppressed, thus a 2D pure polarization microstructures was obtained [21,22].…”

Optical and Physical Applications of Photocontrollable Materials: Azobenzene-Containing and Liquid Crystalline Polymers

“…Two-dimensional photonic crystals with optical anisotropy based on molecular alignment caused by the polarization modulation of interference fields were demonstrated using photo-crosslinkable liquid crystalline polymers. Ono and coworkers reported both optical properties and theoretical treatment [58,59]. The side-chain type LCP has a cinnamic moiety in its terminal region [60,61].…”

Twisted phase gratings induced by photoregulated mesogenic molecules on the surface of photoreactive polymer liquid crystal film

“…9,[15][16][17][18][19] The two-dimensional polarization gratings can diffract the laser beam and convert the polarization states at the same time. We have studied photoinduced optical anisotropy in the photocrosslinkable polymer liquid crystal ͑PPLC͒.…”