1550-nm time-domain study of ErAs:GaAs photoconductive switches as a function of the erbium concentration

We present the performance of ultrafast ErAs:GaAs photoconductive-switch antennas measured with a 1550-nm time-domain spectrometer. A 1%- and 2%-Er ErAs:GaAs PC switch were tested and showed detected transmitted frequencies up to at least 2.5 and 4.0 THz, respectively, with a dynamic range of ~50 and ~55 dB below ~200 GHz.