$T^{-3}$-shift in a short-baseline atomic interferometer-gravimeter

Abstract

This paper presents the first experimental observation and investigation of a lineshape-asymmetry-caused shift (LACS) in a short-baseline atomic interferometer-gravimeter. It is shown that this shift scales inversely with the cube of the free evolution time, $\propto T^{-3}$, and can lead to a noticeable systematic error in the measured value of the gravitational acceleration g at the level of 0.1-1 mGal ($T\approx$ milliseconds). The obtained results are in good agreement with our previous theoretical studies and highlight the importance of accounting for LACS in high-precision absolute measurements of g in compact atomic gravimeters.

Figures (3)

• Figure 1: (Color online) Chirping of the Raman beam frequency: (a) interferometric sequence (blue curve) and frequency chirp scheme (orange curve); (b) typical resonance corresponding to the two-photon transition $|F=1, m_F=0\rangle \rightarrow |F=2, m_F=0\rangle$.
• Figure 2: (Color online) Observation of the LACS shift in an atomic interferometer-gravimeter: (a) typical interference signal (red curve, blue curve — fit based on the theoretical model Yudin_2025) obtained for $T=110~\mu$s without averaging (each point represents a single experimental cycle); (b) fragment of the central interference fringe (red curve, blue — fit) and the corresponding lock-in amplifier output signal (orange curve) fitted with a straight line (black dashed-dotted line) over its linear region (highlighted in pink); (c–g) plots of the LACS shift $\Delta_{LACS}$ versus Raman beam detuning $\delta_D$ for different free-evolution intervals $T$.
• Figure 3: (Color online) Plot of the proportionality coefficient $\beta$ as a function of the free-evolution time $T$.