Ion-irradiated In0.53Ga0.47As based photoconductive antennas excited at 1.55 μm for time domain terahertz spectroscopy

We present a time-domain terahertz spectroscopy set up based on Er:fiber laser which delivers pulses at 1.55 mum wavelength and that integrates photoconductive antennas made on heavy ion-irradiated In_0.53Ga_0.47As material as emitter and detector. A detailed study of the effect of the carrier lifetime on the terahertz signal characteristics has been performed. Improvements in bandwidth and in average power of the emitted terahertz radiation are observed with the decrease of the carrier lifetime on the emitter. The average power radiated is comparable with or greater than that emitted by similar low temperature grown GaAs photoconductive antennas excited by 780 nm wavelength optical pulses.