Department of physics, Shanghai Jiao Tong University, Shanghai 200240, P.R. China
Photoinduced changes in a Sudan I doped PMMA thin film were investigated. The dependence of photoinduced birefringence of the thin film on light intensity was studied, with a continuous wave (CW) 532 nm laser as pump light and a CW 650 nm laser as probe light. For all the light intensities (100–1000 mW/cm2), the thin film possessed large photoinduced birefringence (Δn ~ 10−4). With a CW 532 nm laser at relatively low light intensity, a reversible polarization hologram has been recorded in the thin film. Moreover, Z-scan measurements showed that the thin film possessed large nonlinear refractive index (−7.93 × 10−5 cm 2/W) and nonlinear absorption coefficient (−5.50 W/cm) under a CW 532 nm excitation.
(Received May 5 2008)
(Revised July 24 2008)
(Accepted September 16 2008)
(Online publication December 6 2008)