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Enhanced Quantum Magnetometry with a Femtosecond Laser-Written Integrated Photonic Diamond Chip

MetadataDetails
Publication Date2025-04-21
JournalNano Letters
AuthorsYanzhao Guo, Giulio Coccia, Vinaya Kumar Kavatamane, Argyro N. Giakoumaki, Anton N. Vetlugin
InstitutionsPolitecnico di Milano, Nanyang Technological University
Citations3

Ensemble negatively charged nitrogen-vacancy centers in diamond are promising quantum sensors. To optimize their sensitivity, it is crucial to increase the number of spins sampled and maximize their coupling to the detection system without degrading their spin properties. In this paper, we demonstrate enhanced quantum magnetometry via a buried laser-written waveguide in diamond with 4.5 ppm nitrogen-vacancy centers. The waveguide-coupled nitrogen-vacancy centers exhibit spin coherence properties comparable to those of nitrogen-vacancy centers in pristine diamond. Waveguide-enhanced magnetic field sensing is demonstrated in a fiber-coupled integrated photonic chip, where probing an increased volume of high-density spins results in 63 pTĀ·Hz<sup>-1/2</sup> of DC magnetic field sensitivity and 20 pTĀ·Hz<sup>-1/2</sup> of AC magnetic field sensitivity. This on-chip sensor realizes at least an order of magnitude improvement in sensitivity compared to the conventional confocal detection setup, paving the way for high-sensitivity quantum magnetometry with nitrogen-vacancy ensembles.