Abstract

Photon echo phenomena from individual atoms or molecules with inhomogeneously broadened optical transition line have been investigated for a long time. Recently a new kind of photon echo has been observed^{[1, 2]} which results from electron-hole excitations in semiconductors. A presence of a disorder (impurities, structure imperfections, etc) leads to scattering of the carriers which can drastically change the ballistic character of their propagation to the diffusive that. A question of interest is an influence of the disorder on the signal of photon echo. Being determined by correlations between the forward and reversed time evolution of the system the photon echo and its stationary analogy optical phase conjugation are expected to reveal so called weak localization effects. For the optical phase conjugation these striking effects have been studied in Ref. ³, ⁴. For the photon echo the importance of such effects has been noticed recently.^[5] For two particular models (of localized holes and of ordered conduction band) considered in Ref. ⁵, the expressions for the echo signal can be straightforwardly reduced to the well-known correlation functions of the localization theory.

© 1992 IQEC