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Proceedings Paper

Femtosecond time-resolved refractive index changes in CdSSe
Author(s): Eric C. Fox; Edesly J. Canto-Said; Henry M. van Driel
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Paper Abstract

Light deflection and diffraction scattering techniques have been used in pump-probe geometries to measure the temporal and irradiance dependences of refractive index changes induced by intense 120 fsec (lambda) equals 620 nm pulses in 100 micrometers thick crystals of bulk CdS and CdS0.75Se0.25 at 295 K. Instantaneous and long lived negative refractive index changes are observed. The instantaneous changes are attributed to optical Stark and two- photon resonance effects while the long lived changes are attributed to free carrier bandfilling effects. The irradiance dependences of the different contributions are discussed in terms of a model in which attenuation is dominated by two-photon absorption. The rise and decay times associated with the bandfilling nonlinearity have allowed us to identify a carrier cooling time of 2 psec, and a carrier lifetime which can be as short as 6 psec for pump irradiances in excess of 300 GW/cm2. Possible mechanisms for the carrier recombination are discussed.

Paper Details

Date Published: 21 October 1992
PDF: 7 pages
Proc. SPIE 1677, Ultrafast Lasers Probe Phenomena in Semiconductors and Superconductors, (21 October 1992); doi: 10.1117/12.137682
Show Author Affiliations
Eric C. Fox, Univ. of Toronto (Canada)
Edesly J. Canto-Said, Univ. of Toronto (Canada)
Henry M. van Driel, Univ. of Toronto (Canada)

Published in SPIE Proceedings Vol. 1677:
Ultrafast Lasers Probe Phenomena in Semiconductors and Superconductors
Robert R. Alfano, Editor(s)

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