摘要: High resolution nonlinear laser spectroscopy studies are reported for excitationrelaxation associated with the excitation optical nonlinearity are reported for at room temperature and low temperature in GaAs/AlGaAs multiple quantu... 展开 High resolution nonlinear laser spectroscopy studies are reported for excitationrelaxation associated with the excitation optical nonlinearity are reported for at room temperature and low temperature in GaAs/AlGaAs multiple quantum wells. Using a new method of cw frequency domain four wave mixing, we show that relaxation of the room temperature nonlinear optical response is characterized by free carrier recombination and ambipolar diffusion. At low temperature, the excitation relaxation for localized excitons is dominated by phonon assisted tunneling. In addition, we use four wave mixing methods to eliminate contributions to the excitation line shape from inhomogeneous broadening. The observed line shape is highly asymmetric and shows the prescence of spectral diffusion due to the phonon assisted tunneling associated with the excitation relaxation. 收起