Transient photoinduced current in dye-doped polymer and polymer-dispersed liquid crystals

Results are reported on the experimental observation and detailed treatment of photoinduced de currents, which arise in both dye-doped polymer and dis persion of liquid-crystalline droplets in the same polymer under cw laser-b eam illumination. These currents reveal transient behavior, i.e., a relaxat ion to zero value after an initial increase. This growth is monotonic by lo w Values of the laser radiation intensity, but it changes to oscillating be havior by higher values. A preliminary theoretical approach, which is based on experimentally observed features, reveals good qualitative agreement wi th current temporal-envelope measurements. The observation of these photoin duced currents is another evidence for the photorefractive nature of the li ght-induced diffraction gratings, which were observed earlier in the same m aterials. (C) 2001 Optical Society of America OCIS codes: 160.2900, 160.532 0, 160.5140, 160.5470, 160.3710, 260.5150.