Development of a Carbon-Monoxide Rotational-Transition-Stabilized 3.1THz Quantum Cascade Laser for Terahertz Frequency Standard

We have stabilized the frequency of a 3.1 THz quantum cascade laser (QCL) to the rotational transition J=27← 26 of carbon-monoxide (CO). The achieved frequency stability was 5×10
^-9
in the Allan standard deviation at 10s averaging time. The absolute frequency of the THz-QCL was determined to be 3097909.4 (0.1) MHz, which agrees to the previous report within the uncertainty [1]. This CO-stabilized THz-QCL has a potential to be served as an unprecedented frequency standard in THz region.