Tunable broadband frequency-multiplied terahertz sources

Continued advances in Schottky diode frequency multiplier technology enable solid-state submillimeter-wave and terahertz sources with higher output power tunable over broader bandwidths than have been previously demonstrated. For example, 630 muW of continuous-wave power were measured at 900 GHz at room temperature and 1.4 mW at 920 GHz from the same frequency multiplier chain when cooled to 77 K. The 3 dB bandwidth of this chain is about 100 GHz. Simulations predict that an additional tripler driven by this new 900 GHz tripler chip could produce 1 to 2 muW at 2.7 THz when operated at 77 K, which is sufficient to pump a superconducting heterodyne mixer. We present these recent results as well as summarize the current state-of-the-art of JPL frequency multiplied sources. Finally, we review the limitations of our current generation of frequency multipliers to predict that future advances in amplifier and diode technology should enable at least a ten-fold increase in available tunable output power from solid state frequency-multiplied sources.