Transition from an exponential to a linear increase of the energy density of the spectral component of picosecond stimulated GaAs emission upon gain saturation
Abstract:
At the beginning of 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 appears in it. The increase with time in the energy density of each spectral component of the emission occurs exponentially until the onset of the gain saturation regime. In this regime, the increase is already linear. In the present work, it is experimentally determined, depending on which parameters of the spectral component of the emission and according to what law, the following changes: (a) the time (counted from the beginning of the stimulated emission) after which the transition from exponential growth to linear one occurs; (b) the energy density of the component at the “moment” of the transition; (c) gain at the stage of linear increase in the component energy density. The Conclusion summarizes phenomena found in our works, occurring during the gain saturation.
Keywords:stimulated picosecond emission, gallium arsenide, spectral components of emission, characteristic relaxation time of emission, gain saturation, energy transport of charge carriers, stimulated recombination rate.
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