Effects of thermal modulation on diffraction in liquid crystal composite gratings.

A microperiodic structure composed of polymer and liquid crystal (LC) phases, called holographic polymer dispersed LC, is fabricated by a photo-induced phase separation technique using LC composites with different physical properties, such as refractive indices and clearing points. Effects of thermal modulation on diffraction properties of LC composite gratings are experimentally investigated in the viewpoints of polarization and temperature dependences. The diffractions based on the change of refractive index induced by the nematic-isotropic transition of LCs with the increase of temperature are applied for a holographic image reconstruction.