Biphotonic holographic recording in a liquid crystalline cyanoazobenzene side-chain polymethacrylate. Polarization, intensity, and relief gratings

Biphotonic holographic recording has been performed on thin films of a side-chain liquid crystalline p-cyanoazobenzene polymethacrylate. Polarization and intensity holographic gratings have been recorded by irradiation of the films with blue incoherent light and simultaneous or subsequent illumination with the red light pattern generated by the interference of two properly polarized beams from a He–Ne laser. The influence of temperature and illumination conditions on the diffraction efficiency of those gratings has been studied. Surface topography of the films has been explored using a profilometer. The appearance of relief gratings using biphotonic processes has been observed only in gratings recorded with simultaneous illumination of blue light and an intensity modulated light pattern of the red light.