Laser intracavity absorption magnetometry for optical quantum sensing

Abstract:Intracavity absorption spectroscopy (ICAS) is a well-established technique for detecting weak absorption signals with ultrahigh sensitivity. Here, we extend this concept to magnetometry using nitrogen-vacancy (NV) centers in diamond. We introduce laser intracavity absorption magnetometry (LICAM), a concept that is in principle applicable to a broader class of optical quantum sensors, including optically pumped magnetometers. Using an electrically driven, edge-emitting diode laser that operates self-sustainably, we show that LICAM enables highly sensitive magnetometers operating under ambient conditions. Near the lasing threshold, we achieve a 475-fold enhancement in optical contrast and a 180-fold improvement in magnetic sensitivity compared with a conventional single-pass geometry. The experimental results are accurately described by a rate-equation model for single-mode diode lasers. From our measurements, we determine a projected shot-noise-limited sensitivity in the $\mathrm{pT}\,\mathrm{Hz}^{-1/2}$ range and simulate that, with realistic device improvements, shot-noise limited sensitivities down to the $\mathrm{fT}\,\mathrm{Hz}^{-1/2}$ scale are attainable.

arXiv:2512.24951 [quant-ph]

(or arXiv:2512.24951v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2512.24951 Focus to learn more arXiv-issued DOI via DataCite

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