We study the power-limiting properties of photoanisotropic azobenzene films with low-power lasers. The <i>trans-cis</i> photoisomerization and molecular reorientation of azobenzene molecules induced by polarized laser beams result in intensity-dependent anisotropic effects. Consequently, the transmittance of the input beam that passes through the film between two crossed polarizers becomes enhanced at low intensities and clamped at high intensities. The limiting threshold is adjustable by changing the intensity of excitation beam.
© 2003 Optical Society of America
(190.4360) Nonlinear optics : Nonlinear optics, devices
(230.4320) Optical devices : Nonlinear optical devices
(260.1440) Physical optics : Birefringence
(310.6860) Thin films : Thin films, optical properties
Pengfei Wu, Reji Philip, Ramesh B. Laghumavarapu, Janakriam Devulapalli, Devulapalli V. G. L. N. Rao, Brian R. Kimball, Masato Nakashima, and Barry S. DeCristofano, "Optical Power Limiting with Photoinduced Anisotropy of Azobenzene Films," Appl. Opt. 42, 4560-4565 (2003)