Abstract

Degenerate (single-color) and nondegenerate (two-color) time-resolved Z-scan techniques, with femtosecond time resolution, have been implemented to measure the magnitude and dynamical processes of the optical nonlinearities of ZnSe. In the time-resolved Z-scan spectra a reversal of sign in the refractive-index change Δn as a function of time delay was observed. A bound electronic contribution with a resolution limited response (~200 fs) gave rise to a positive Δn at zero time delay, whereas a free-carrier contribution resulted in a negative Δn at longer time delays. The free-carrier contribution to Δn has two initial rapid relaxation components with time constants of a few picoseconds and a few tens of picoseconds, respectively. The long-lived carriers also contributed to a slow relaxation component in Δn on a nanosecond time scale.

© 1996 Optical Society of America

Time-resolved Z-scan measurements of optical nonlinearities

J. Wang, M. Sheik-Bahae, A. A. Said, D. J. Hagan, and E. W. Van Stryland
J. Opt. Soc. Am. B 11(6) 1009-1017 (1994)

Characterization of dynamic optical nonlinearities by continuous time-resolved Z-scan

David O. Caplan, Gregory S. Kanter, and Prem Kumar
Opt. Lett. 21(17) 1342-1344 (1996)

Measurement of nondegenerate nonlinearities using a two-color Z scan

M. Sheik-Bahae, J. Wang, R. DeSalvo, D. J. Hagan, and E. W. Van Stryland
Opt. Lett. 17(4) 258-260 (1992)

Measurement of free-carrier nonlinearities in ZnSe based on the Z-scan technique with a nanosecond laser

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Opt. Lett. 19(15) 1116-1118 (1994)

Z-scan technique for investigation of the noninstantaneous optical Kerr nonlinearity

Bing Gu, Hui-Tian Wang, and Wei Ji
Opt. Lett. 34(18) 2769-2771 (2009)