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arXiv · 2602.10931

Probe-assisted Depopulation Pumping in Low-pressure Alkali-metal Vapor Cells for Magnetometry

M. E. Limes·J. Smoot·J. Perez·J. Freeman·C. Amano-Dolan·D. Peters·W. Lee
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Abstract

For precision atomic magnetometry, inert buffer gas is included in alkali-metal vapor cells to significantly broaden hyperfine transitions, which facilitates optical pumping and reduces diffusive relaxation, while also providing non-radiative excited state quenching. We show low-buffer gas pressure (below 50 Torr) alkali vapor cells with resolved hyperfine manifolds can also yield high-performance magnetometers. For high polarization in $^{87}$Rb, we optically pump $F=2$ states with narrow linewidth $σ_+$ light, while tuning a probe beam to depopulate $F=1$ states ($Δν= 6.8$ GHz from $F=2$). The probe tuning then also provides $F=2$ detection with high optical rotation and low probe broadening; we demonstrate top-bottom gradiometry, within a single 25 Torr, 0.5 cc cell, that yields an Earth's field free-precession magnetometer sensitivity of 18 fT/$\sqrt{\text{Hz}}$ with a 1 kHz bandwidth, as well as RF magnetometer sensitivity of 12 fT/$\sqrt{\text{Hz}}$ in a small band about 110 kHz.

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M. E. Limes, J. Smoot, J. Perez, J. Freeman, C. Amano-Dolan, D. Peters, W. Lee. 2026-02-11. Probe-assisted Depopulation Pumping in Low-pressure Alkali-metal Vapor Cells for Magnetometry. https://arxiv.org/abs/2602.10931

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