Laser frequency stabilization for continuous-wave laser enhanced direct frequency comb spectroscopy system

Abstract

We present the observation of high-precision direct frequency comb spectroscopy excited by an optical frequency comb and a diode laser when each of them drives one step of the two-photon transition in a rubidium vapor system. We demonstrate a stable and low noise system by directly locking the frequency of the continuous-wave laser to the rubidium two-photon transition. The frequency stability of a diode laser via the two-photon transition locking technique is 8 × 10−11 for a 1 s gate time and 3 × 10−12 for 1000 s. It proves to be a potential technique for locking the diode laser with high stability. We chose a suitable optical frequency comb pulse and the frequency of the diode laser to fulfill the double-resonance condition. These techniques eliminate spectrum line overlap and would benefit spectroscopy measurements.