Generation and detection of coherent terahertz waves using two photomixers

A general technique has been demonstrated at microwave and submillimeter-wa ve frequencies for photoconductive sampling in the frequency domain using p hotomixers and continuous-wave laser diodes. A microwave version in which t wo photomixers were coupled by a transmission line was developed to quantit atively test the concept from 0.05 to 26.5 GHz. A quasioptical version usin g antenna-coupled photomixers was demonstrated from 25 GHz to 2 THz. Such a system can outperform systems based on time-domain photoconductive samplin g in frequency resolution, spectral brightness, system size, and cost. (C) 1998 American Institute of Physics. [S0003-6951(98)03152-0].