TERAHERTZ PHOTOMIXING WITH DIODE-LASERS IN LOW-TEMPERATURE-GROWN GAAS

Recent optical heterodyne measurements with distributed-Bragg-reflecto r diode-laser pumps demonstrate that low-temperature-grown (LTG) GaAs photomixers will be useful in a compact all-solid-state terahertz sour ce. Electrical 3 dB bandwidths as large as 650 GHz are measured in mix ers with low electrode capacitance. These bandwidths appear to be inde pendent of pump-laser wavelength over the range 780-850 nm. Shorter wa velength pumping results in a significant reduction of the bandwidth. The best LTG-GaAs photomixers are used to generate coherent continuous -wave output radiation at frequencies up to 5 THz. (C) 1995 American I nstitute of Physics.