Abstract

Accumulated photon echo¹ (AccPE) is an ultra-sensitive tool for studying optical dephasing of excitations in solids. The essential prerequisite for the succesful application of this technique is the presence of metastable states in the optical pumping cycle, preventing the system from a quick return to the ground state. A frequency grating in the ground state may than be formed and serve to create a stimulated echo. The technique has been applied to study long-lived optical impurity centers and bound excitons in solids. Here we present the first exploratory measurements on short-lived excitons in semi-insulating GaAs, and we will discuss the accumulation mechanisms. These mechanisms hold promise for general application of AccPE to study excitons in semiconductors.

© 1992 The Author(s)