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arXiv · 2308.12933

Quantum-enhanced magnetometry at optimal number density

Charikleia Troullinou·Vito Giovanni Lucivero·Morgan W. Mitchell
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Abstract

We study the use of squeezed probe light and evasion of measurement back-action to enhance the sensitivity and measurement bandwidth of an optically-pumped magnetometer (OPM) at sensitivity-optimal atom number density. By experimental observation, and in agreement with quantum noise modeling, a spin-exchange-limited OPM probed with off-resonance laser light is shown to have an optimal sensitivity determined by density-dependent quantum noise contributions. Application of squeezed probe light boosts the OPM sensitivity beyond this laser-light optimum, allowing the OPM to achieve sensitivities that it cannot reach with coherent-state probing at any density. The observed quantum sensitivity enhancement at optimal number density is enabled by measurement back-action evasion.

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Charikleia Troullinou, Vito Giovanni Lucivero, Morgan W. Mitchell. 2023-08-24. Quantum-enhanced magnetometry at optimal number density. https://doi.org/10.1103/physrevlett.131.133602

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