Femtosecond time-resolved pump-probe spectroscopy is used to investigate the ultrafast carrier dynamics of Ge/SiGe quantum wells grown on a Si substrate. Pronounced nonequilibrium effects in the relaxation dynamics of the optically injected carrier distributions are observed and analyzed using a microscopic many-body theory. Transient population inversion and optical gain is obtained on a femtosecond time scale for excitation at energies slightly above the lowest direct quantum-well transition.
Ultrafast nonlinear optical response of photoexcited Ge/SiGe quantum wells: Evidence for a femtosecond transient population inversion
CHRASTINA, DANIEL;ISELLA, GIOVANNI;
2009-01-01
Abstract
Femtosecond time-resolved pump-probe spectroscopy is used to investigate the ultrafast carrier dynamics of Ge/SiGe quantum wells grown on a Si substrate. Pronounced nonequilibrium effects in the relaxation dynamics of the optically injected carrier distributions are observed and analyzed using a microscopic many-body theory. Transient population inversion and optical gain is obtained on a femtosecond time scale for excitation at energies slightly above the lowest direct quantum-well transition.File in questo prodotto:
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