Diffraction from holographic gratings in polymer-dispersed liquid crystals recorded by means of polarization light patterns

An experimental and theoretical study of holographic gratings recorded exposing a homogeneous mixture of prepolymer and liquid crystals to a polarization light pattern is reported. The polarization pattern is obtained by a superposition of two waves with orthogonal linear polarization. This technique is based on the possibility of controlling the liquid-crystal alignment inside the droplets, through the photoalignment, during the photoinduced polymerization and the phase separation processes that precede the formation of polymer-dispersed liquid crystals. Diffraction gratings with a large anisotropy were observed, indicating a particular alignment of the liquid crystals inside the droplets. An investigation of the polarization properties of this grating and an explanation of the obtained results are presented. (C) 2001 Optical Society of America.