Pulsed THz time domain system with ErAs:In(Al)GaAs photoconductors

We report on 1550 nm driven ErAs:In(Al)GaAs photoconductors implemented as both source and detector in a THz time domain system. The system reaches a peak dynamic range of 80 dB with a source and receiver laser power of 20 mW each. We report in particular on the saturation properties of the emitter. Even with incident optical powers of up to 80 mW, we hardly see any saturation. We demonstrate the capabilities of the setup by spectroscopy of a lactose sample.