Depletion-electric-field-induced changes in second-harmonic generation from GaAs

Abstract

Experiments reveal that the near surface second-order nonlinear optical susceptibility, ${\mathrm{\chi }}^{\mathrm{}\left(2\right)\mathrm{}}$(2ω,ω,ω), is significantly affected by band-bending-induced electric fields in the depletion region of GaAs(001). Both n- and p-type GaAs samples exhibit a reduction of the bulk second-order susceptibility ${\mathrm{\chi }}_{\mathit{y}\mathit{x}\mathit{z}}^{\mathrm{}\left(2\right)\mathrm{}}$ independent of electric field direction. A three band theoretical model was used to qualitatively explain these observations.