Resonantly enhanced bound-continuum intersubband second harmonic generation in optimized asymmetric semiconductor quantum wells

Abstract

A systematic procedure applied to a step-asymmetric quantum well in order to maximize intersubband bound–continuum second-order susceptibility is described. The possibility is explored of obtaining resonantly enhanced nonlinear optical susceptibilities in quantum wells with two bound and a continuum resonance state as the dominant 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 AlxGa1−xAs alloy based wells designed for pump photon energies in range of ℏω=200–300 meV indicate a perspective of employing continuum states in resonant second harmonic generation at higher photon energies.