Fluorescence thermometry enhanced by the quantum coherence of single spins in diamond

TLDR

The study demonstrates fluorescence thermometry techniques with sensitivities approaching 10 mK Hz⁻¹ᐟ² using spin‑dependent photoluminescence of nitrogen vacancy centers in diamond. The methods employ dynamical decoupling protocols that translate thermally induced shifts in NV spin resonance frequencies into large fluorescence changes. The protocols increase thermometry spin coherence times by 45‑fold, yielding a 7‑fold sensitivity improvement, and work across a broad temperature range and both finite and near‑zero magnetic fields. This versatility suggests that the quantum coherence of single spins could be practically leveraged for sensitive thermometry in a wide variety of biological and microscale systems.

Abstract

We demonstrate fluorescence thermometry techniques with sensitivities approaching 10 mK⋅Hz −1/2 based on the spin-dependent photoluminescence of nitrogen vacancy (NV) centers in diamond. These techniques use dynamical decoupling protocols to convert thermally induced shifts in the NV center's spin resonance frequencies into large changes in its fluorescence. By mitigating interactions with nearby nuclear spins and facilitating selective thermal measurements, these protocols enhance the spin coherence times accessible for thermometry by 45-fold, corresponding to a 7-fold improvement in the NV center’s temperature sensitivity. Moreover, we demonstrate these techniques can be applied over a broad temperature range and in both finite and near-zero magnetic field environments. This versatility suggests that the quantum coherence of single spins could be practically leveraged for sensitive thermometry in a wide variety of biological and microscale systems.