Nonlinear optical properties of the electron-hole plasma in Al0.52Ga0.48As

Abstract

A dense electron-hole plasma is created in Al0.52Ga0.48As using picosecond excitation with high excess energy. Its properties are studied by time-resolved photoluminescence and transient transmission spectroscopy. Simultaneous emission out of the indirect X and the direct Γ band is observed. Alloy disorder strongly influences the bimolecular recombination by allowing for quasidirect transitions and stimulated emission out of the indirect X band. The electron-hole plasma, whose electrons reside mainly in the X valleys, causes strong optical nonlinearities at the direct absorption edge. A persistent absorption bleaching and large induced refractive-index changes due to band filling of the valence band and induced absorption due to band-gap renormalization are observed.