Laser-induced holographic light scattering in a liquid-crystalline azobenzene-containing polymer

The holographic scattering phenomenon was observed and studied in detail for azobenzene-containing polymer system. It was found that irradiation of 25-μm-thick samples of the polymer with a single linearly polarized laser beam results in the appearance of a band with the maximum in the vicinity of irradiating wavelength in polarized extinction spectra. The band is completely polarized along the polarization direction of irradiating light. The shape of the band is exceedingly sensitive to rotation of the sample with respect to the spectrometer probe beam. An analogous band appears upon the irradiation of the sample with circularly polarized light. The observed phenomenon is presumably similar to holographic scattering, reported previously in photorefractive crystals and some photopolymers. A detailed description of the observed spectral changes is presented. The sensitivity of the effect towards probe light polarization and direction, irradiating light wavelength, and temperature is discussed.