Microwave synthesis from a continuous-wave terahertz oscillator using a photocarrier terahertz frequency comb

We report low-noise microwave synthesis from radiation with a frequency of 0.3 THz using a photocarrier frequency comb in a photoconductive antenna. The synthesized microwave signal at 1 GHz is phase coherent to the 0.3 THz radiation and has a fractional instability of 1×10(-15) within 300 s averaging times and single-sideband phase noise of -105 dB/Hz at a 100 Hz offset from the carrier. This terahertz (THz)-to-microwave synthesizer is capable of being a THz frequency divider, which would be indispensable to not only THz metrology but also future high-speed wireless networks.