Terahertz time-domain spectroscopy system using rhodium doped InGaAs antennas: 637 μW peak power and 110 dB dynamic range

We present a terahertz (THz) time-domain spectroscopy system that employs photoconductive antennas based on rhodium (Rh) doped InGaAs both as emitter and receiver. Due to the unique electronic and dynamic properties of InGaAs: Rh, the system shows a record performance with 6.5 THz spectral bandwidth and 110 dB dynamic range. In addition, 637 μW of THz power could be generated out of 28 mW optical power with an InGaAs: Rh emitter, which is, to the best of our knowledge, the highest value reported for an all fiber coupled device.