Concept of a microscale vector magnetic field sensor based on nitrogen-vacancy centers in diamond

A three-component magnetic field sensor scheme based on optically detected magnetic resonance (ODMR) in negatively charged nitrogen-vacancy centers is implemented and investigated experimentally. The central part of the scheme is a 0.01mm3 diamond crystal, optically pumped and interrogated through an optical fiber; combined RF excitation of hyperfine triplets in the ODMR spectrum is used to increase the signal-to-noise ratio. Methods that allow for efficient identification of ODMR spectral lines while minimizing the number of the sensor "dead" zones are proposed and tested. The scheme's sensitivity to magnetic field vector components, estimated on the basis of the signal-to-noise-to-linewidth ratio, is found to be 1.5nT[middot]Hz super(-1/2). The operational frequency range of the scheme is 0-100 Hz.