Abstract: Since the development of laser locking technology in the 1980s,ultrastable lasers have played an important role in high-precision optical quantum time-frequency metrology,such as optical clocks,gravitational wave detection,cavity quantum electrodynamics,and satellite-ground communication.The Pound-Drever-Hall(PDH) technology provides a good way to stabilize free running lasers.Here,by utilizing such method,we lock the 852 nm wavelength laser to the resonance frequency of the ultrastable cavity to achieve the highly-stabilized laser output.In the experiment,the quality factor of the ultrastable resonator reached 10¹⁰,the finesse reached 200,000,and the 1 second frequency stability of the output laser reached 5.2×10^-15 with laser linewidth of 2.3 Hz.This continuous laser with such frequency stability will provide robust technical support for an 852 nm clock laser with good correlation with Cs atoms.

Key words: Pound-Drever-Hall(PDH) locking, Laser frequency stabilization, Narrow linewidth laser