By treating laser-induced optical Kerr nonlinearity as a noninstantaneous decaying process, we present the pulse-duration-dependent Z-scan analytical expressions for an arbitrary aperture and an arbitrary nonlinear magnitude. This theory has the capacity to characterize the third-order nonlinear refraction induced by a laser pulse with its temporal duration being much longer than or comparable to the recovery time of the nonlinear effect. Through Z-scan measurements at different pulse durations, the nonlinear refractive coefficient and the recovery time could be determined unambiguously and simultaneously. Furthermore, the theory can be utilized to confirm whether the measured optical Kerr nonlinearity is instantaneous or noninstantaneous with respect to the given pulse duration.
© 2009 Optical Society of America
Original Manuscript: May 8, 2009
Revised Manuscript: July 28, 2009
Manuscript Accepted: August 17, 2009
Published: September 9, 2009
Bing Gu, Hui-Tian Wang, and Wei Ji, "Z-scan technique for investigation of the noninstantaneous optical Kerr nonlinearity," Opt. Lett. 34, 2769-2771 (2009)