Nonlinear optical effects in germanium in the THz range: THz-pump - THz-probe measurement of carrier dynamics

摘要

Nonlinear high intensity THz transmission measurements were made on Ge, showing nonlinear optical effects in the THz range including self-phase modulation and absorption saturation. THz-pump - THz-probe measurements were performed on n-type Ge, GaAs, and Si to follow the ultrafast free carrier dynamics that underlie the nonlinear effects seen in the transmission measurements. Complex relaxation behavior was observed, arising from inter- and intra-valley scattering in the conduction bands of these semiconductors.