Generation of 460 GHz radiation by photomixing in low-temperature-grown MBE GaAs

We report on the fabrication and characterization of LT GaAs photomixers for generation of 460 GHz radiation. Resonant cavity structures and devices with various finger contacts geometry are used to enhance the photomixer performance. The DC responsivity shows only slight suppression with increased optical power in the range of 0.17-45 mW, i.e. space-charge effects are suppressed. A good agreement between the microwave power and DC responsivity (P_out ∼ R²) is obtained. Our results indicate that significant improvement in the output power, up to ∼1 μW of microwave radiation, can be obtained.