Eur. Phys. J. D (2015) 69: 166
https://doi.org/10.1140/epjd/e2015-60080-1

Regular Article

Magnetic imaging with an ensemble of nitrogen-vacancy centers in diamond

¹ Thales Research & Technology, 1 av. Augustin Fresnel, 91767 Palaiseau CEDEX, France
² Laboratoire des Sciences des Procédés et des Matériaux, CNRS and Université Paris 13, 93340 Villetaneuse, France
³ Institut für Experimentelle Physik II, University Leipzig, Leipzig, Germany
⁴ Laboratoire Aimé Cotton, CNRS, Université Paris-Sud and Ecole Normale Supérieure de Cachan, 91405 Orsay, France

^a e-mail: thierry.debuisschert@thalesgroup.com

Received: 6 February 2015
Received in final form: 25 May 2015
Published online: 2 July 2015

Abstract

The nitrogen-vacancy (NV) color center in diamond is an atom-like system in the solid-state which specific spin properties can be efficiently used as a sensitive magnetic sensor. An external magnetic field induces Zeeman shifts of the NV center levels which can be measured using optically detected magnetic resonance (ODMR). In this work, we quantitatively map the vectorial structure of the magnetic field produced by a sample close to the surface of a CVD diamond hosting a thin layer of NV centers. The magnetic field reconstruction is based on a maximum-likelihood technique which exploits the response of the four intrinsic orientations of the NV center inside the diamond lattice. The sensitivity associated to a 1 μm² area of the doped layer, equivalent to a sensor consisting of approximately 10⁴ NV centers, is of the order of 2 μT/√Hz. The spatial resolution of the imaging device is 480 nm, limited by the numerical aperture of the optical microscope which is used to collect the photoluminescence of the NV layer. The effectiveness of the method is illustrated by the accurate reconstruction of the magnetic field created by a DC current inside a copper wire deposited on the diamond sample.