Photon Avalanche Effect In Quantum Wells: Controlling Light With Light

A new mechanism of controlling the absorption of high-intensity signal light with frequency omega and intensity j(omega) by complementary control light with frequency Omega > 2 omega and 2 or 3 orders of magnitude lower intensity j(omega) is proposed. The mechanism is based on the photon avalanche effect in quantum wells. The electron concentrations in size-quantization subbands and conduction band continuum and the absorbed power of signal light are obtained as functions of the intensities j(omega) and j(Omega) and the time of exposure to laser radiation t. It is established that the resulting dependences exhibit well-pronounced threshold behavior. For example, at j(Omega) similar to 0.2 - 1 kW/cm(2) and t similar to 0.1 - 5 ns, it is possible to control the absorption of signal light, so that the absorption of this light is practically lacking at intensities j(omega) below the threshold intensity (40 - 200 kW/cm(2)) and becomes very strong at intensities above the threshold intensity. The case when control light Omega is the third harmonic of high-intensity signal light is also considered. (C) 2019 Optical Society of America