FEMTOSECOND TIME-RESOLVED Z-SCAN INVESTIGATIONS OF OPTICAL NONLINEARITIES IN ZNSE

Citation
Ky. Tseng et al., FEMTOSECOND TIME-RESOLVED Z-SCAN INVESTIGATIONS OF OPTICAL NONLINEARITIES IN ZNSE, Optics letters, 21(3), 1996, pp. 180-182
Citations number
16
Categorie Soggetti
Optics
Journal title
ISSN journal
01469592
Volume
21
Issue
3
Year of publication
1996
Pages
180 - 182
Database
ISI
SICI code
0146-9592(1996)21:3<180:FTZIOO>2.0.ZU;2-9
Abstract
Degenerate (single-color) and nondegenerate (two-color) time-resolved Z-scan techniques, with femtosecond time resolution, have been impleme nted to measure the magnitude and dynamical processes of the optical n onlinearities of ZnSe. In the time-resolved Z-scan spectra a reversal of sign in the refractive-index change Delta n as a function of time d elay was observed. A bound electronic contribution with a resolution l imited response (similar to 200 fs) gave rise to a positive Delta n at zero time delay, whereas a free-carrier contribution resulted in a ne gative hn at longer time delays. The free-carrier contribution to Delt a n has two initial rapid relaxation components with time constants of a few picoseconds and a few tens of picoseconds, respectively. lived carriers also contributed to a slow relaxation component in Delta n on a nanosecond time scale. (C) 1996 Optical Society of America