Corrections to enhanced optical nonlinearity of superlattices

Abstract

In recent publications, a large enhancement of the third order nonlinear optical susceptibility was predicted for GaAs–GaAlAs superlattices, as a result of the band nonparabolicities introduced by the additional periodicity of the superlattice. These predictions, based on the tight binding model, are here extended to the more realistic Kronig–Penney model. Results show that corrections to tight binding are non-negligible; however, enhancements of χ(3) are still large, but reduced by approximately 30%–50% over previous estimates.