Theory of high gain transient energy transfer in GaAs and Si

Rate equations for carrier number densities and wave equations for optical fields are solved numerically to investigate transient energy transfer (TET) from a strong pump beam to a weak probe via the free-carrier nonlinearity in GaAs and Si. The calculations of TET include arbitrary ratio of pulse length to diffusion time, pump depletion, free-carrier absorption, and two-photon absorption. The calculations provide guidance on the optimal choice of sample thickness, free-carrier cross section, and two-photon absorption coefficient for obtaining high TET gains in semiconductors.<
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