Functional dependences of the maximum energy density of the spectral component of stimulated picosecond GaAs emission at gain saturation. Residual characteristic relaxation time of emission

During high-power optical picosecond pumping of the GaAs layer of the Al$_x$Ga$_{1-x}$As–GaAs–Al$_x$Ga$_{1-x}$As heterostructure, stimulated picosecond emission arises in it. It has been experimentally revealed how, upon saturation of the emission gain, the maximum energy density of its spectral component and the time to reach this density depend on the photon energy, on the parameters of the amplification and relaxation of the component. It follows from these dependences that the indicated density and time are influenced by the slowing down of the transport of nonequilibrium carriers in the energy space. The slowdown is caused by the interaction of carriers with emission. It has been found that as the diameter of the active region approaches zero, the measured characteristic relaxation time of the component tends to the theoretical universal residual relaxation time prolonged due to the indicated transport slowdown.