Ultrafast self-modulation of the optical absorption spectrum under conditions of both the ultrashort optical pumping and superluminescence in GaAs
- Russian Academy of Sciences, Institute of Radio Engineering and Electronics (Russian Federation)
Self-modulation of the optical absorption spectrum is observed during the picosecond photogeneration of charge carriers and intense superluminescence in GaAs. As the picosecond delay {tau} of the probing pulse with respect to the pump pulse is varied in the region of {tau} < 0, the local points of the absorption intensification (juts) shift along the spectrum (the modulation resembles a running wave). As the value of {tau} is varied in the vicinity of {tau} = 0, the juts in the spectrum arise and disappear at approximately fixed photon energies (the modulation resembles a standing wave). At certain photon energies, the dependence of the rate of variation in the absorption coefficient d{alpha}/d{tau} on {tau} is found to be modulated by pulsations, similarly to the previously observed modulation of the picosecond stimulated emission from GaAs. Presumably, the spectrum self-modulation represents (and, thus, reveals) the modulation of the electron distribution in the conduction band. This modulation is caused by the fact that the evolution of the electron-population depletion at the bottom of the conduction band during superluminescence reflects (due to the electron-phonon interaction) on the population of the upper energy levels in the band.
- OSTI ID:
- 21088512
- Journal Information:
- Semiconductors, Vol. 40, Issue 7; Other Information: DOI: 10.1134/S1063782606070098; Copyright (c) 2006 Nauka/Interperiodica; Article Copyright (c) 2006 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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