Related papers: Photoswitchable radicals as reporter spins for quantum sensing with spin defects in diamond

Photoswitchable radicals as reporter spins for quantum sensing with spin defects in diamond

URL: http://arxiv.org/abs/2510.05406v1
Date: Mon, 06 Oct 2025 21:55:05 GMT
Title: Photoswitchable radicals as reporter spins for quantum sensing with spin defects in diamond
Authors: Lakshmy Priya Ajayakumar, David J. Durden, Aksshay Nandakumar Regeni, Mingcai Xie, Swastik Hegde, Gustavo Aldas, Kyle Haggard, Mikael P. Backlund,
Abstract summary: rapid decay of target signal strength with distance from the sensor presents a key challenge in nanoscale magnetic sensing.<n>We introduce a strategy to overcome this limitation by using radical anions formed from rhodamine-derived dyes as reporter spins localized to the diamond surface.<n>We experimentally demonstrate their coherent manipulation and detection using single, shallow NV centers for readout.
Score: 0.0
License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Abstract: The rapid decay of target signal strength with distance from the sensor presents a key challenge in nanoscale magnetic sensing with nitrogen-vacancy (NV) centers in diamond, limiting both sensitivity and spatial resolution. Here we introduce a strategy to overcome this limitation by using radical anions formed from rhodamine-derived dyes as reporter spins localized to the diamond surface. These radicals, generated through photoreduction, are optically identifiable and stable on timescales exceeding an hour. We experimentally demonstrate their coherent manipulation and detection using single, shallow NV centers for readout. We observe heterogeneity in the local magnetic environments of the photoactivated spins from site to site, likely due to variations in inter-radical couplings across our measurements. Looking forward, our approach enables correlative nanoscale magnetic and optical imaging, and opens new pathways toward single-molecule magnetic resonance studies.

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