[7a-PA3-1~17] 3.2 Equipment optics and materials

[7a-PA3-1] Optical Property Analysis of Liquid Crystal Gratings Fabricated by Photopolymerization with Non-Polarized Light

〇Miho Aizawa¹, Kyohei Hisano¹, Norihisa Akamatsu¹, Atsushi Shishido^1,2 (1.Lab. for Chem. & Life Sci., Tokyo Tech., 2.PRESTO, JST)

Keywords:Photopolymerization, Diffraction Grating, Molecular Alignment

In recent years, many groups have been engaged in research and development related to functional optical materials. In particular, the interest for polarization holography has been growing because polarization holographic gratings can be used for various kinds of applications. These gratings have been fabricated by employing a photoalignment method with photoreactive molecules. In the polarization holographic technique, the periodic change of molecular alignment is induced by irradiation of two coherent writing beams with orthogonal polarization. These processes are widely investigated but have some problems such as necessity of linearly or circularly polarized light and specific photoreactive compounds that limit degree of freedom of molecular design. We have recently found a novel photoalignment process by masked photopolymerization of anisotropic monomers. In this procedure, we also observed that a periodic structure was formed spontaneously in the obtained polymer film. In this study, we fabricated gratings by dynamic photopolymerization process. We evaluated the alignment behavior of the films with a polarized optical microscope and examined optical property of the gratings by the observation of diffracted light. Moreover, we also observed that the periodic structures are changed by the control of crosslinker concentration.