APPLICATION OF BRAGG-CONFINED SEMICONDUCTOR STRUCTURES FOR HIGHER-ENERGY RESONANT INTERSUBBAND 2ND-HARMONIC GENERATION

The existence of bound electron states above the barrier in Bragg-conf ined structures is proposed as a means of extending the range of photo n energies suitable for resonant intersubband second-harmonic generati on beyond what is available in conventional quantum-well structures. W ithin the envelope function approximation the expressions are first de rived for energies and wave functions of bound states in Bragg structu res with an asymmetric perturbation layer. A systematic procedure, bas ed on supersymmetric quantum mechanics, is then described for the desi gn of optimized structures to get the maximum nonlinear susceptibility , An example of a calculation for the case of pump photon energy (h) o ver bar omega approximate to 240 meV is also presented and the design aspects of such structures are considered.