Highly-Accurate Terahertz Frequency Comb toward Establishment of Terahertz Frequency Standard

Abstract

Absolute frequency measurement system in THz region is an indispensable tool for the establishment of THz frequency standard. We have developed a THz frequency counter based on THz comb using a photoconductive antenna with a femtosecond-pulse fiber laser. The THz counter has the fractional frequency uncertainty of 1.7 × 10^‒17 at 0.3 THz and an instability of 4.1 × 10^‒14/τ up to an averaging time of 10⁴s.