Optical pump-terahertz probe spectroscopy utilizing a cavity-dumpedoscillator-driven terahertz spectrometer

摘要

A terahertz spectrometer capable of steady-state and time-resolvednmeasurements over the 0.1-3.5-THz spectral region has been built. Thisnspectrometer routinely produces and detects terahertz pulses thatnexhibit signal-to-noise ratios (SNRs) greater than 6000 in the timendomain and a spectral noise door of magnitude 2.7×10-4.nHence, the spectrometer achieves nearly four decades of dynamic range innthe frequency domain. Two pulse generation processes are observed tongive rise to the measured terahertz pulse. High-quality opticalnpump-terahertz probe data on ⟨111⟩ GaAs samples are presented,ndemonstrating the applicability of this spectrometer to the study ofnoptically induced dynamical processes. Non-Drude relaxation behavior isnobserved in the transient terahertz spectra