Bound-Continuum Intersubband Transition Based Optical Nonlinearities in Semiconductor Quantum Wells

The possibility is explored of obtaining resonantly enhanced nonlinear optical susceptibilities in semiconductor quantum wells with two bound states and the resonant state in continuum as the third state. This would significantly extend the range of input radiation photon energies that may be frequency-doubled under resonance conditions in realistic structures. Calculation for the AlGaAs alloy based wells designed for the second harmonic generation of 240meV radiation indicate the usefulness of this approache.