Optical injection and control in germanium: Thirty-band k.p theory

The optical injection of spin, current, and spin current in bulk Ge is investigated theoretically. Spin-polarized carriers can be photoexcited by monochromatic circularly polarized light through either one- or two-photon processes. With simultaneous omega and 2 omega irradiation, currents can be injected and coherently controlled by interference of one- and two-photon transition amplitudes. We calculate the spectral dependence of these all-optical effects, including anisotropy and dichroism effects and a careful description of the hole spin injection. Injection at the E-1 resonance is studied thanks to an adaptive grid and a full-zone k.p band structure.