SrBi<sub>2</sub>Ta<sub>2</sub>O<sub>9</sub> (SBT) thin films on quartz substrates were prepared by use of the pulsed-laser deposition technique. The nonlinear refractive indices, n<sub>2</sub> , of the SBT films were measured by use of z-scan techniques with picosecond pulses. Large negative nonlinear refractive indices of 3.84 and 3.58cm<sup>2</sup>/GW were obtained for the wavelengths 532 nm and 1.064μm , respectively. The two-photon absorption coefficient was determined to be 7.3 cm/GW for 532 nm. The limiting behavior of SBT thin film on a quartz substrate was investigated in an f/5 defocusing geometry by use of 38-ps-duration, 532-nm, 1.064μm laser excitation.
© 2001 Optical Society of America
Y. Z. Gu, W. F. Zhang, D. H. Gu, and F. X. Gan, "Nonlinear response and optical limiting in SrBi2Ta2O9 thin films," Opt. Lett. 26, 1788-1790 (2001)