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Proceedings Paper

Intersubband relaxation time for excitons in the n=2 subbands of GaAs quantum wells
Author(s): Bipul Pal; Arvind S. Vengurlekar
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Paper Abstract

We resonantly excite the n=2 excitons at 8 K in 13 nm and 17.5 nm GaAs quantum wells using 0.5 ps pulses from a Ti-Sapphire laser and perform four wave mixing (FWM) measurements. The exciton dephasing time is deduced by fitting the FWM spectra to a numerical solution of the optical Bloch equations for the excitonic resonance. The finite pulse width and presence of small inhomogeneous broadening are taken into account. The homogeneous linewidth thus obtained at different low excitation intensities has a linear dependence on the intensity. The zero intensity intercept is essentially governed by the n=2 exciton lifetime due to intersubband relaxation, the pure transverse dephasing contribution being relatively less important. We deduce the exciton lifetime to be 0.9 ps and 2.6 ps for the 13 nm and 17.5 nm QWs, respectively.

Paper Details

Date Published: 11 June 2002
PDF: 8 pages
Proc. SPIE 4643, Ultrafast Phenomena in Semiconductors VI, (11 June 2002); doi: 10.1117/12.470411
Show Author Affiliations
Bipul Pal, Tata Institute of Fundamental Research (India)
Arvind S. Vengurlekar, Tata Institute of Fundamental Research (India)

Published in SPIE Proceedings Vol. 4643:
Ultrafast Phenomena in Semiconductors VI
Kong-Thon F. Tsen; Jin-Joo Song; Hongxing Jiang, Editor(s)

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