Optimization of resonant second- and third-order nonlinearities in step and continuously graded semiconductor quantum wells

Methods for systematic optimization of step-graded and continuously graded ternary alloy based quantum wells (QW's), in respect to second- or third-order intersubband nonlinear susceptibilities at resonance, are discussed. The use of these methods is examplified on the design of Al/sub x/Ga/sub 1-x/N and Al/sub x/Ga/sub 1-x/As-based QW's intended for resonant second harmonic or third harmonic generation with h/spl omega/=116 meV or h/spl omega/=240 meV pump photon energies, the objective being the largest susceptibility achievable with the chosen material. The obtained results exceed those previously reported in the literature.