All-Optical Technique Maps Magnetic Fields Without Microwaves

Feifei Zhou and colleagues at the College of Metrology Measurement and Instrument, in collaboration with Nanyang Technological University and Southern University of Science and Technology, present an all-optical method using van der Waals quantum sensors based on negatively charged boron vacancy centres in hexagonal boron nitride. The method offers a microwave-free strategy for wide-field magnetometry by utilizing the magnetically sensitive ground-state level anti-crossing of these centres, enabling precise determination of external magnetic fields through monitoring level shifts. The team achieved a photon shot-noise-limited sensitivity of 67.1 μT/√Hz, representing roughly a threefold improvement over existing optical detection methods, alongside a spatial resolution of about 1μm per pixel.…