Fig. 1. Scheme of the experimental setup: (a) without focus displacement correction and (b) with focus displacement correction.
Fig. 2. Frequency and sample thickness dependence of the THz beam radius in the detector crystal in the off- and in-focus configurations.
Fig. 3. THz-TDTS of high-resistivity (100) GaAs with a thickness of 990 μm in the off- and in-focus configuration: (a) time-domain data and (b) frequency-domain spectra.