NONLINEAR OPTICAL-PROPERTIES OF TYPE-II QUANTUM-WELLS

G R OLBRIGHT, W S FU, J F KLEM, H M GIBBS, G KHITROVA, R PON, B FLUEGEL, K MEISSNER, N PEYGHAMBARIAN, R BINDER, I GALBRAITH, S W KOCH

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Abstract

Experimental and theoretical investigations of the near-band-gap optical nonlinearities in type-II GaAs/AlAs quantum wells are reported. The temporal evolution of the optical nonlinearities of different samples grown at our two different laboratories is analyzed by comparing femtosecond results at different pump-probe time delays with nanosecond measurements at different sample temperatures. The quasi-cw measurements at low temperatures show exciton bleaching and a pronounced heavy-hole exciton blueshift, which is absent at elevated plasma temperatures (congruent-to 100 K). Femtosecond spectra show a delayed onset of the exciton blueshift consistent with hole-plasma cooling in the absence of electrons. The results are analyzed using many-body theory assuming complete electron-hole charge separation. We show that the presence of a one-component plasma modifies the nonlinear optical behavior of the GaAs layer and results in dramatically different properties compared to type-I quantum-well structures.

Original languageEnglish
Pages (from-to)3043-3053
Number of pages11
JournalPhysical Review B: Condensed Matter and Materials Physics
Volume44
Issue number7
Publication statusPublished - 15 Aug 1991

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