Dissipative Parametric Gain and Multiphoton Effects in Quantum GaAs/AlGaAs Superlattice

A cavityless dissipative parametric gain in quantum GaAs/AlGaAs superlattice is demonstrated and discussed. Using a waveguide-based setup under the biasing of dc and microwave pump, emission lines, corresponding to the simultaneous multiphoton processes in the superlattice, were observed. It was shown that the incident electromagnetic wave experiences transformation into a slow longitudinal electrostatic wave inside the superlattice, ensuring hence the gain levels exceeding 1000 cm$^{-1}$.