Generation of coherent cw-terahertz radiation using a tunable dual-wavelength external cavity laser diode

A tunable dual-wavelength external cavity laser diode (2-lambda-ECL) was us ed to generate tunable coherent cw-terahertz (THz) radiation by photomixing in a biased photoconductive antenna fabricated on a low-temperature-grown (LTG)-GaAs film. The 2-lambda-ECL oscillated at the two output modes simult aneously with a frequency separation from 250 GHz to 2.1 THz in the same ca vity. We demonstrated that the frequency of the emitted THz radiation corre sponded to the difference frequency between the two modes of the diode lase r. The tunable 2-lambda-ECL, due to its compact design and ease of optical alignment, is a promising laser source for the generation of tunable cw-THz radiation by photomixing.