This paper describes thermally enhanced in‐plane and out‐of‐plane reorientation of mesogenic groups in copolymer liquid‐crystal (CPLC) films that have a photo‐cross‐linkable 4‐(4′‐methoxycinnamoyl)biphenyl (MCB) side group and a 4‐methoxybiphenyl (4MB) side group. The side groups are cross‐linked by irradiation with linearly polarized ultraviolet (LPUV) light and subsequent annealing. Due to axis‐selective photo‐cross‐linking, a small negative optical anisotropy is observed for all CPLCs after exposure to LPUV light. When the composition of the 4MB comonomer is less than 45 mol‐%, thermal treatment in the liquid‐crystalline temperature range causes in‐plane reorientation of the film and results in an in‐plane order parameter of 0.71. In contrast, when the composition of the 4MB is increased, out‐of‐plane reorientation is generated. Three‐dimensional molecular reorientation and inclined out‐of‐plane reorientation are achieved by adjusting the exposure angle. Angular dependence of UV absorption spectrum of film 3. The inset shows a conoscope observation of the film. The film was annealed at 130 °C for 10 min.magnified imageAngular dependence of UV absorption spectrum of film 3. The inset shows a conoscope observation of the film. The film was annealed at 130 °C for 10 min.

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Three kinds of methacrylate polymer liquid crystals (PLCs); a copolymer PLC (PLC) substituted with a photo-cross-Linkable 4-(4'-methoxycinnamoyl)oxybiphenyl (MCB) side group and a 4-methoxybiphenyl (4MB) side group (P1), a CPLC with a MCB side group and a 4-cyanobiphenyl (4CN) side group (P2) , and a PLC with a photocross-linkable 4-cinnamoyloxybiphenyl side group (P3), are synthesized . The thin films of these polymers are applied to a birefringent film by irradiation with linearly polarized ultraviolet (LPUV) light and subsequent annealing. Due to axis-selective photo-crosslinking, a small negative optical anisotropy is observed for all CPLCs after exposure to LPUV light. Thermal treatment in the liquid crystalline temperature range for Pl causes in-plane reorientation and results in an in-plane order parameter of 0.71 . In contrast, outof-plane reorientation is generated for P2 and P3. Three-dimensional molecular reorientation and inclined out-of-plane reorientation can be controlled by adjusting the exposure angle. The inclination direction is dependent on the type of the liquid crystalline phase and the side group.

In this paper, we propose a ring-type grating in which grating vectors formed by periodic molecular alignments are superimposed radially. Depending on incident polarization states, the anisotropic gratings generate polarization dependencies for the ring-like first order diffraction. To determine the polarization states of incident light for both single and multi-wavelengths, we attempted to extract the optical intensity distribution on the ring-like diffraction from each single-shot diffraction image. In addition, a system that enables the detection of spatial modulation of optical birefringence is proposed. Finally, we concluded that the optical intensity distribution on the circumference of the ring-like diffraction has sufficient potential to be available.