Cyclic behavior of ultrafast self-modulation of the light-absorption spectrum under conditions of pump and stimulated emission in GaAs
- Russian Academy of Sciences, Institute of Radio Engineering and Electronics (Russian Federation)
- Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)
Under picosecond photogeneration of charge carriers in GaAs, accompanied by intense stimulated emission of the semiconductor itself, ultrafast self-modulation of its light-absorption spectrum takes place, which consists in the appearance of regions of local absorption enhancement (bumps) in the spectrum. The ultrafast self-modulation is found to exhibit a cyclic behavior; i.e., the pattern of the self-modulation of the spectrum (the number and spectral position of the bumps) is repeated after a certain time T{sub c} falling in the picosecond range. The cycle period T{sub c} varies over the time span of the pump pulse and depends on the pulse energy, which means that T{sub c} is a function of the pump intensity. Assuming that self-modulation of the absorption reflects self-modulation of the charge-carrier energy distribution in GaAs under pumping, experimental results can be formulated as follows: in the process of the ultrafast self-modulation, deviations of the occupancies of different energy levels from the Fermi distribution evolve with time in a mutually related way; the distribution of the occupancy depletion in the conduction band repeats cyclically in time; and the cycle period decreases as the intensity of the pump increases.
- OSTI ID:
- 21255621
- Journal Information:
- Semiconductors, Vol. 42, Issue 9; Other Information: DOI: 10.1134/S1063782608090078; Copyright (c) 2008 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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