Laser-frequency stabilization with differential single-beam saturated absorption spectroscopy of 4He atoms

• Main Authors: Guo, H. (Author), Liu, Y. (Author), Peng, X. (Author), Wang, B. (Author), Wang, H. (Author)
• Format: Article
• Language: English
• Published: American Institute of Physics Inc. 2022
• Subjects: Absorption spectroscopy; Atom lasers; Commonmode; Doppler effect; Fiber lasers; First derivative; Frequency fluctuation; Frequency stability; Frequency stabilization; He atoms; Laser frequency stabilization; Lasing frequency; Optical noise; Saturated-absorption spectroscopy; Single-beam; Stabilization
• Online Access: View Fulltext in Publisher

 Differential single-beam saturated-absorption spectroscopy (DSSAS) is proposed to stabilize lasing frequency and suppress Doppler-broadened background and common-mode optical noise. The spectral first-derivative demodulated signal of metastable He4 atoms is used as an error signal to stabilize a fiber laser around 1083 nm. Experimental results show that, compared with existing non-DSSAS frequency stabilization, DSSAS stabilization produces better stability and lower fluctuations, especially for frequency-noise-corrupted lasers. In DSSAS stabilization, for data acquired over 7000 s, the root mean square frequency fluctuation of the fiber laser is 16.4 kHz, and the frequency stability described by the modified Allan deviation is 4.1 × 10-12 at 100 s. Even for a defective laser with poor frequency stability, the proposed scheme demonstrates experimentally high capability of noise suppression and reduces the frequency fluctuations by two orders of magnitude. Given its simplicity and compact design, frequency stabilization by DSSAS is promising for quantum-sensor applications, such as atomic magnetometers, atomic gyroscopes, and atomic clocks. © 2022 Author(s).