Microwave-free imaging magnetometry with nitrogen-vacancy centers in nanodiamonds at near-zero field

• DOI: 10.1103/physrevapplied.23.034001
• Publication Date: 2025-03-03T15:03:31Z
• Authors: Saravanan Sengott...; Omkar Dhungel; Mariusz Mrózek; Arne Wickenbrock; Dmitry Budker; Wojciech Gawlik; Adam M. Wojciecho...

Magnetometry using nitrogen-vacancy (N-V) color centers in diamond predominantly relies on microwave spectroscopy. However, microwaves may hinder certain studies involving biological systems or thin conductive samples. This work demonstrates a wide-field, microwave-free imaging magnetometer utilizing N-V centers in nanodiamonds by exploiting the cross-relaxation feature near zero magnetic fields under ambient conditions without applying microwaves. For this purpose, we measure the center shift, contrast, and linewidth of zero-field cross relaxation in 140-nm nanodiamonds dropcast on a current-carrying conductive pattern while scanning a background magnetic field, achieving a sensitivity of 4.5μT/Hz. Our work allows for applying the N-V zero-field feature in nanodiamonds for magnetic-field sensing in the zero- and low-field regimes and highlights the potential for microwave-free all-optical wide-field magnetometry based on nanodiamonds.

Published by the American Physical Society 2025