The dynamic behavior of a holographic grating induced in a homeotropically aligned dye-doped liquid-crystal film is investigated. In the presence of an applied dc voltage, photoexcited azo dyes induce a photorefractive grating and then diffuse and are adsorbed onto cell substrates. The reorientation of liquid crystals as a result of adsorbed dyes leads to a phase grating that is phase shifted 90° from the photorefractive grating. Competition of these two gratings induces two-beam coupling of the writing beams, initially transferring energy from beam 1 to beam 2 and then, after a pause, from beam 2 to beam 1.
© 2001 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(090.2900) Holography : Optical storage materials
(190.5330) Nonlinear optics : Photorefractive optics
(210.4810) Optical data storage : Optical storage-recording materials
Andy Y.-G. Fuh, C.-C. Liao, K.-C. Hsu, C.-L. Lu, and C.-Y. Tsai, "Dynamic studies of holographic gratings in dye-doped liquid-crystal films," Opt. Lett. 26, 1767-1769 (2001)