Terahertz Optoelectronics: InGaAs photomixers generate and detect terahertz radiation

摘要

With contributions from the University of Leeds (Leeds, England) and the University of Manchester (Manchester, England), Researchers at TeraView (Cambridge, England) have demonstrated what they are calling the first all-optoelectronic continuous-wave (CW) terahertz photomixing system using indium gallium arsenide (InGaAs) photomixers. Compatible with optical-fiber excitation wavelengths, the system uses low-temperature (LT)-grown InGaAs devices for both emitters and coherent homodyne detectors. Conventional photoconductive terahertz systems are usually based on femtosecond-speed pulsed lasers driving optical switches fabricated from LT-GaAs. In this approach, CW terahertz radiation is emitted and detected by photomixing two CW lasers in a photo-conductor. The frequency difference of the lasers is tuned to the terahertz region and the conductance of the device is modulated at the difference frequency.