Abstract

The use of quantum interference effects to control the properties of semiconductors via phased optical beams has been a subject of strong recent interest.^1,2 Previously our group showed² that interference between one and two photon absorption processes at 2ω and ω respectively can inject currents in crystalline semiconductors. In the context of nonlinear optics, the current injection tensor can be understood as a physically divergent piece of χ⁽³⁾ (0;ω,ω>,–2ω). Here we show that for certain non-centrosymmetric crystals, current injection can also occur via quantum interference of absorption processes involving orthogonally polarized photons from a single color beam. Related processes have been previously discussed phenomenologically³ in connection with anisotropic carrier scattering and photovoltaic effects under the name of circular photocurrent.

© 1999 Optical Society of America