Formation of Holographic Grating by Means of Polymer Liquid Crystal Containing Azobenzene Moieties as Both Mesogens and Photoresponsive Chromophores

Abstract

We investigated the formation of holographic grating by means of polymer liquid crystal containing azobenzene moieties as both mesogens and photoresponsive chromophores. First-order diffraction signal of probe beam (He-Ne laser, λ=632.8 nm) was immediately observed when writing beams (Ar^+ laser, λ=488 nm) were turned on. The diffraction efficiency reached approximately 20 %. Furthermore, the diffraction efficiency was affected by the polarization direction of the probe beam. When the direction was parallel to the initial molecular alignment, the diffraction efficiency showed the maximum value. It suggests that the grating was based on the periodic distribution of the refractive indices of nematic (N) and isotropic (I) phases due to the photochemical N to I phase transition. In addition, we succeeded in recording the image hologram of a photomask as an object.