Realization of the 6Li Cold Atom Interferometer and Precise Measurement of Recoil Frequency

We report a cold atom interferometer based on the lightest alkali metal 6Li and measure its recoil frequency precisely, measuring the fine -structure constant on a preliminary basis. To overcome the challenges associated with magnetic -field sensitivity caused by the half -integer spin of atoms, a magnetically insensitive Raman transition and a conjugated Ramsey-Borde interferometer involving crossed Raman beams and coherence time >2. 3 ms is realized. The error in the angles between Raman beams is eliminated using four sets of interferometers developed based on geometric relationships. The measured recoil frequency & omega;r is 2 & pi; x73 672. 789(36) Hz, and the fine -structure constant is 1/137. 035976 (33). These values indicate the most accurate measurements for 6Li obtained using the reported atom interferometer. The implementation of the 6Li cold atom interferometer not only enriches the elements of atom interferometers, but also has great potential in the field of precision measurement due to its high recoil frequency.