All-semiconductor room-temperature terahertz time domain spectrometer

We report what we believe to be the first demonstration of an all-semiconductor room-temperature terahertz time domain spectrometer. An optical Stark mode-locked vertical-external-cavity surface-emitting laser with 480 fs pulses at 1044 nm was used to illuminate low-temperature-grown photoconductive antennae with 5 mum-gap bow-tie-shaped electrodes. The coherently detected spectrum has a bandwidth close to 1 THz, in which water absorption lines at 0.555 and 0.751 THz can be resolved.