Frequency Stabilization and Linewidth Narrowing with Modulation Transfer Spectroscopy
ZHANG Xi1,2,3, LIU Hui1,2,3, JIANG Kunliang1,2,3, WANG Jinqi1,2,3, XIONG Zhuanxian1,2, HE Lingxiang1,2† , LÜ Baolong1,21. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, Hubei, China; 2. Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, Hubei, China; 3. School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
We report laser frequency stabilization with modulation transfer spectroscopy (MTS) on 85Rb atoms. With both PZT (piezo-electric transducer) slow-loop feedback and current fast- loop feedback to the laser head, we get a linewidth narrowing less than 5 kHz simultaneously. Laser injection to a laser diode and frequency beating with another polarization spectroscopy based stabilization setup are also employed to check the narrow linewidth property. With the help of the technique, a linewidth around kHz-level laser is obtained and pave the way for the locking of the lattice laser of ytterbium clock with transfer cavity technique. The setup can be used as a frequency reference for precise frequency control of atomic clock system.
Key words: modulation transfer spectroscopy; frequency stabilization; linewidth; long-term drift
 Schioppo M, Brown R C, McGrew W F, et al. Ultrastable optical clock with two cold-atom ensembles [J]. Nature Photonics, 2017, 11(1): 48-52.
 Nicholson T L, Campbell S L, Hutson R B, et al. Systematic evaluation of an atomic clock at 2×10–18 total uncertainty [J]. Nature Communications, 2015, 6: 6896.
 International Committee for Weights and Measures. Recom- mended values of standard frequencies for applications including the practical realization of the metre and secondary representations of the second “171Yb neutral atom, 6s21S0 – 6s6p 3P0 unperturbed optical transition” [EB/OL]. [2017- 05-25]. http://www.bipm.org/utils/common/pdf/mep/171Yb_ 518THz_2015.pdf.
 Derevianko A, Pospelov M. Hunting for topological dark matter with atomic clocks [J]. Nature Physics, 2014, 10(12): 933-936.
 Jiang Y Y, Ludlow A D, Lemke N D, et al. Making optical atomic clocks more stable with 10–16-level laser stabiliza- tion [J]. Nature Photonics, 2011, 5(3): 158-161.
 Riedle E, Ashworth S H, Farrell Jr J T, et al. Stabilization and precise calibration of a continuous-wave difference- frequency spectrometer by use of a simple transfer cavity [J]. Review of Scientific Instruments, 1994, 65(1): 42-48.
 Shirley J H. Modulation transfer processes in optical heterodyne saturation spectroscopy [J]. Opt Lett, 1982, 7(11): 537-539.
 McCarron D J, King S A, Cornish S L. Modulation transfer spectroscopy in atomic rubidium [J]. Measurement Science and Technology, 2008, 19(10): 252-253.
 Qi X H, Chen W L, Yi L, et al. Ultra-stable rubidium- stabilized external-cavity diode laser based on the modulation transfer spectroscopy technique [J]. Chinese Physics Letters, 2009, 26(4): 113-115.
 Wang W L, Xu X Y. Modulation transfer spectroscopy of ytterbium atoms in a hollow cathode lamp [J]. Chinese Physics Letters, 2011, 28(3): 33202-33204.
 Sun D L, Zhou C, Zhou L, et al. Modulation transfer spectroscopy in a lithium atomic vapor cell [J]. Optics Express, 2016, 24(10): 10649-10662.
 Cheng B, Wang Z Y, Wu B, et al. Laser frequency stabilization and shifting by using modulation transfer spectroscopy [J]. Chinese Physics B, 2014, 23(10): 242-247.
 Kale Y B, Ray A, Singh N, et al. Modulation transfer in Doppler broadened Λ system and its application to frequency offset locking [J]. The European Physical Journal D-Atomic, Molecular, Optical and Plasma Physics, 2011, 61(1): 221-229.
 Hall J L, Hollberg L, Baer T, et al. Optical heterodyne saturation spectroscopy [J]. Applied Physics Letters, 1981, 39(9): 680-682.