Time-resolved Raman scattering in gallium-arsenide multiple quantum well structures

This thesis describes an optical study of the intersubband relaxation of carriers in GaAs multiple quantum well structures. For this investigation the application of the conventional Raman scattering technique was extended to the picosecond time domain. Inelastic light scattering from the elementary intersubband excitations of an electron-hole plasma reveals both the absolute carrier density and the occupancy of the electronic subbands of a GaAs quantum well. The major result of this investigation concerns the role of the intersubband scattering processes in the relaxation of carriers following their excitation in a GaAs quantum well by a short optical pulse. Carriers generated on the second subband of a wide quantum well relax towards the bottom of the well by the emission of acoustic phonon. Their lifetime is found equal to 325...