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arXiv · 2009.02371

NV-Diamond Magnetic Microscopy using a Double Quantum 4-Ramsey Protocol

Connor A. Hart·Jennifer M. Schloss·Matthew J. Turner·Patrick J. Scheidegger·Erik Bauch·Ronald L. Walsworth
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Abstract

We introduce a double quantum (DQ) 4-Ramsey measurement protocol that enables wide-field magnetic imaging using nitrogen vacancy (NV) 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-$\mu$m-thick NV layer in a macroscopic diamond chip, the DQ 4-Ramsey protocol provides volume-normalized DC magnetic sensitivity of $\eta^\text{V}=34\,$nTHz$^{-1/2} \mu$m$^{3/2}$ across a $125\,\mu$m$ \,\times\,125\,\mu $m field of view, with about 5$\times$ 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 enable imaging of dynamic, broadband magnetic sources such as integrated circuits and electrically-active cells.

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Connor A. Hart, Jennifer M. Schloss, Matthew J. Turner, Patrick J. Scheidegger, Erik Bauch, Ronald L. Walsworth. 2020-09-04. NV-Diamond Magnetic Microscopy using a Double Quantum 4-Ramsey Protocol. https://doi.org/10.1103/physrevapplied.15.044020

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