中国物理B ›› 2026, Vol. 35 ›› Issue (6): 67102-067102.doi: 10.1088/1674-1056/ae4c71

• • 上一篇    下一篇

Suppression of moving-potential effect in an optical Raman lattice scheme for spin-orbit-coupled alkaline-earth fermions

Rui Wu(吴瑞)1,2,3,†, Han Zhang(张涵)1,2,3,†, Tao Deng(邓涛)1,2,3,4, Wen-Wei Wang(王文伟)1,2,3, and Xibo Zhang(张熙博)1,2,3,4,‡   

  1. 1 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China;
    2 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China;
    3 Hefei National Laboratory, Hefei 230088, China;
    4 Beijing Academy of Quantum Information Sciences, Beijing 100193, China
  • 收稿日期:2026-01-29 修回日期:2026-02-24 接受日期:2026-03-03 发布日期:2026-06-05
  • 通讯作者: Xibo Zhang E-mail:xibo@pku.edu.cn
  • 基金资助:
    This work was supported by the Chinese Academy of Sciences Strategic Priority Research Program (Grant No. XDB35020100), the Hefei National Laboratory, and the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301903).

Suppression of moving-potential effect in an optical Raman lattice scheme for spin-orbit-coupled alkaline-earth fermions

Rui Wu(吴瑞)1,2,3,†, Han Zhang(张涵)1,2,3,†, Tao Deng(邓涛)1,2,3,4, Wen-Wei Wang(王文伟)1,2,3, and Xibo Zhang(张熙博)1,2,3,4,‡   

  1. 1 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China;
    2 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China;
    3 Hefei National Laboratory, Hefei 230088, China;
    4 Beijing Academy of Quantum Information Sciences, Beijing 100193, China
  • Received:2026-01-29 Revised:2026-02-24 Accepted:2026-03-03 Published:2026-06-05
  • Contact: Xibo Zhang E-mail:xibo@pku.edu.cn
  • Supported by:
    This work was supported by the Chinese Academy of Sciences Strategic Priority Research Program (Grant No. XDB35020100), the Hefei National Laboratory, and the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301903).

摘要: Optical Raman lattices in ultra-cold alkali-metal and alkaline-earth atoms provide a powerful method to synthesize spin-orbit (SO) coupling. While the ground-state energy splittings (divided by Planck's constant) can reach the range of tens of megahertz in alkali-metal atoms, the typical ground-state energy splittings are on the order of tens of kilohertz or smaller in alkaline-earth atoms (AEAs) such as $^{87}$Sr. For AEAs, because such limited ground-state energy splittings are rather close to the kilohertz-scale recoil energy that is relevant for optical lattice physics, a standard implementation of a two-dimensional (2D) optical Raman lattice can lead to parasitic periodic moving potentials that heat up the atoms and severely limit the atomic lifetime. Recently, an improved optical Raman lattice scheme was proposed and experimentally realized in ultra-cold strontium fermions, which significantly enhanced the lifetime of 2D-SO-coupled fermions. However, a concrete electro-optical setup has yet to be demonstrated, and its control precision needs to be quantified. Here we demonstrate the electro-optical setup of an improved optical Raman lattice scheme that suppresses the effect of moving lattice potentials for alkaline-earth fermions by introducing a sufficiently large frequency separation between two sets of laser polarization components, where each set yields an independent Raman coupling. To quantify the precision of this setup, we feedback-control the relative phase between the two sets of Raman couplings, which is an important parameter characterizing the 1D-2D crossover of SO couplings, and measure the stability of this phase over hour-long periods. We also investigate the optimum range for the applied frequency separation. Our approach provides a useful tool that helps achieve long-lived SO-coupled systems using AEAs.

关键词: spin–orbit coupling, optical Raman lattice, alkaline-earth atoms, ultracold fermions, moving potential

Abstract: Optical Raman lattices in ultra-cold alkali-metal and alkaline-earth atoms provide a powerful method to synthesize spin-orbit (SO) coupling. While the ground-state energy splittings (divided by Planck's constant) can reach the range of tens of megahertz in alkali-metal atoms, the typical ground-state energy splittings are on the order of tens of kilohertz or smaller in alkaline-earth atoms (AEAs) such as $^{87}$Sr. For AEAs, because such limited ground-state energy splittings are rather close to the kilohertz-scale recoil energy that is relevant for optical lattice physics, a standard implementation of a two-dimensional (2D) optical Raman lattice can lead to parasitic periodic moving potentials that heat up the atoms and severely limit the atomic lifetime. Recently, an improved optical Raman lattice scheme was proposed and experimentally realized in ultra-cold strontium fermions, which significantly enhanced the lifetime of 2D-SO-coupled fermions. However, a concrete electro-optical setup has yet to be demonstrated, and its control precision needs to be quantified. Here we demonstrate the electro-optical setup of an improved optical Raman lattice scheme that suppresses the effect of moving lattice potentials for alkaline-earth fermions by introducing a sufficiently large frequency separation between two sets of laser polarization components, where each set yields an independent Raman coupling. To quantify the precision of this setup, we feedback-control the relative phase between the two sets of Raman couplings, which is an important parameter characterizing the 1D-2D crossover of SO couplings, and measure the stability of this phase over hour-long periods. We also investigate the optimum range for the applied frequency separation. Our approach provides a useful tool that helps achieve long-lived SO-coupled systems using AEAs.

Key words: spin–orbit coupling, optical Raman lattice, alkaline-earth atoms, ultracold fermions, moving potential

中图分类号:  (Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect)

  • 71.70.Ej
37.10.Jk (Atoms in optical lattices) 67.85.Lm (Degenerate Fermi gases)