Efficient terahertz devices based on III-V semiconductor photoconductors

A series of planar aperture and dipole antenna structures fabricated on low temperature grown GaAs and InP-based photoconductors have been evaluated as terahertz (THz) emitters and detectors in a time-domain spectroscopy system under pulsed excitation. The combination of large aperture antennas as emitters and short dipole antennas as detectors results in efficient THz devices operating at 800 nm, 1 μm and 1.55 μm excitation wavelengths. The system responses of these materials are among the best ever reported and allow high-quality measurements to be made. Finally, characterisation of a structure able to be biased vertically and its evaluation as THz emitter is reported for the first time. The THz response of this material with a strong THz signal at low-voltage bias makes the development of battery-operated THz devices possible.