INFLUENCE OF CARRIER RELAXATION ON THE DYNAMICS OF STIMULATED-EMISSION IN MICROCAVITY LASERS

The influence of carrier relaxation on the emission dynamics of a semi conductor microcavity laser is investigated using femtosecond optical excitation. For moderate excitation intensities, the dynamics of the o utput laser pulse becomes significantly slower when the photon energy of the pump laser is tuned from the quantum well band-gap energy towar ds higher energies. Theoretical calculations reproduce this trend only if the interaction-induced dephasing of the polarization driven by th e pump pulse, the formation, and relaxation of the nonequilibrium carr ier distribution as well as the chirp of the excitation pulse are take n into account. Additionally, band-structure effects such as excitatio n of light holes influence the thermalization dynamics and lead to dis continuities in the general trend. (C) 1997 American Institute of Phys ics. [S0003-6951(97)04152-1].