N -V -Diamond Magnetic Microscopy Using a Double Quantum 4-Ramsey Protocol
Abstract
We introduce a double quantum (DQ) 4-Ramsey measurement protocol that enables wide-field magnetic imaging using nitrogen-vacancy (N -V ) centers in diamond, with enhanced homogeneity of the magnetic sensitivity relative to conventional single quantum (SQ) techniques. The DQ 4-Ramsey protocol employs microwave-phase alternation across four consecutive Ramsey (4-Ramsey) measurements to isolate the desired DQ magnetic signal from any residual SQ signal induced by microwave pulse errors. In a demonstration experiment employing a 1-μ m -thick N -V layer in a macroscopic diamond chip, the DQ 4-Ramsey protocol provides a volume-normalized dc magnetic sensitivity of ηV=34 nT Hz−1 /2μ m3 /2 across a 125 μ m ×125 μ m field of view, with about 5 × less spatial variation in sensitivity across the field of view compared to a SQ measurement. The improved robustness and magnetic sensitivity homogeneity of the DQ 4-Ramsey protocol enables imaging of dynamic broadband magnetic sources such as integrated circuits and electrically active cells.
- Publication:
-
Physical Review Applied
- Pub Date:
- April 2021
- DOI:
- 10.1103/PhysRevApplied.15.044020
- arXiv:
- arXiv:2009.02371
- Bibcode:
- 2021PhRvP..15d4020H
- Keywords:
-
- Quantum Physics;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Physics - Applied Physics;
- Physics - Instrumentation and Detectors
- E-Print:
- 20 pages, 10 figures