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Photoswitchable Radicals as Reporter Spins for Quantum Sensing with Spin Defects in Diamond
Lakshmy Priya Ajayakumar1,2, David J Durden1,2, Aksshay Nandakumar Regeni1,2
1Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
Researchers developed a new method using rhodamine dye radicals to enhance nanoscale magnetic sensing with nitrogen-vacancy (NV) centers in diamond. This approach improves sensitivity and spatial resolution for magnetic imaging and spectroscopy.
Area of Science:
- Quantum sensing
- Materials science
- Organic chemistry
Background:
- Nanoscale magnetic sensing using nitrogen-vacancy (NV) centers in diamond faces challenges due to signal decay with distance.
- Limited sensitivity and spatial resolution restrict the information obtainable from NV-based magnetic sensing.
Purpose of the Study:
- To overcome the distance-dependent signal decay limitations in NV-based nanoscale magnetic sensing.
- To introduce a novel strategy for enhanced magnetic and optical imaging at the nanoscale.
Main Methods:
- Utilized radical anions derived from rhodamine-based organic dyes localized on a diamond surface.
- Generated radicals via photoreduction, enabling optical identification and long-term stability (exceeding an hour).
- Demonstrated coherent manipulation and detection of these radicals using single, shallow NV centers for readout.
Main Results:
- Successfully demonstrated the coherent manipulation and optical detection of surface-localized rhodamine radicals using NV centers.
- Observed heterogeneity in local magnetic environments, attributed to variations in inter-radical dipolar couplings.
- Confirmed the persistence of photoactivated spins on time scales exceeding one hour.
Conclusions:
- The developed strategy effectively overcomes distance limitations in nanoscale magnetic sensing.
- Enables correlative nanoscale magnetic and optical imaging.
- Opens new avenues for single-molecule magnetic resonance spectroscopy and quantum many-body simulations.
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