Nonlinear optical absorption in semiconductor epitaxial depletion regions

Abstract
We have observed an optically induced decrease in absorption near the band-gap energy in a single-heterostructure Schottky barrier depletion region. Photogenerated carriers created and trapped in the unbiased depletion region cause a dynamic decrease in the absorption. This depletion region electric-field absorption modulator (DREAM) exhibits nonlinear optical absorption which relies upon carrier transport induced by an electric field without an external circuit applied to the device. We demonstrate a factor of two change in absorption at peak powers of 2 mW (0.2 W/cm2).