Experimental Realization of a Mach–Zehnder-Type Internal-State Atom Interferometer in Sodium Spinor BEC

This study demonstrates a Mach–Zehnder-type internal-state atom interferometer in a sodium F = 1 spinor Bose–Einstein condensate (BEC), which is realized by applying a three-pulse radio-frequency sequence (π/2–π–π/2) to manipulate the two magnetic sublevels |1,−1⟩ and |1,0⟩. Phase-scanning experiments show that the visibility remains at a high level across all three pulse stages (V>0.77). In the hold-time scanning measurements, the visibility decays exponentially with hold time, yet the system maintains good coherence. This work establishes a foundation for precision measurements based on internal-state atom interferometers, as the approach simplifies the experimental apparatus while maintaining good quantum coherence and high-contrast interference fringes.