Polarization holographic gratings in an azobenzene side-chain liquid-crystalline polymer

Polarization holographic recording was investigated in a liquid-crystalline azobenzene side-chain polymer. A highly stable polarization holographic grating with the diffraction efficiency of 12.6% was written in the polymer film by two orthogonally linearly polarized 532 nm beams with equal intensities of 150 mW/cm2. The polarization grating was studied with a 633 nm probe beam by surveying the conversion of the polarization state of the probe beam and measuring the dependence of diffraction efficiency on the polarization direction of the probe beam. It was found that the ± first-order diffraction efficiency and the polarization of the diffracted wave depended strongly on the polarization of the readout wave. The unusual diffraction properties of the recorded grating were attributed to the presence of the circular photoinduced birefringence.