Linear and nonlinear optical properties of (GaAs)m/(AlAs)nsuperlattices

We report a full-band-structure calculation of frequency-dependent second-harmonic generation in short-period (GaAs${)}_{\mathit{m}}$/(AlAs${)}_{\mathit{n}}$ superlattices. We use a linear combination of Gaussian orbitals technique, in conjunction with a linearized sampling method, to obtain the dielectric function ε→(ω) and the second-order optical response coefficient χ${\to }^{\mathrm{}\left(2\right)\mathrm{}}$(-2ω;ω,ω). Our results show that the effect of the unique superlattice transitions is more pronounced in χ${\to }^{\mathrm{}\left(2\right)\mathrm{}}$(-2ω;ω,ω) than in ε→(ω).