Abstract

The phase coherence between an electron and the corresponding hole created during a band- to-band optical transition in a semiconductor diminishes with increasing carrier density. The rate at which such dephasing processes occur may however be reduced due to a screened interaction between the carriers. Since the screening between two given carriers is function of their environment, it is expected to change with the dimensionality D of the system. We report here measurements on the carrier-carrier screening behavior in a 2D system (a GaAs-GaA1As quantum well structure), performed by measuring the variation of the dephasing time with carrier density using a femtosecond photon echo technique [1]. We briefly discuss the results with respect to previous measurements made in a 3D system (a bulk sample of GaAs) [2].

© 1990 Optical Society of America