Pico-tesla magnetic field detection with integrated flux concentrators using a multi-frequency modulation technique on the solid nuclear spin in diamonds

Abstract

In this paper, we implement integrated magnetic flux concentrators (MFCs) combined with a multi-frequency modulation method to achieve high-magnetic-detection sensitivity using a nuclear spin on the solid nuclear spin in diamonds. First, we excited the nuclear spin in diamonds using a continuous-wave technique, and a linewidth of 1.37 MHz and frequency resolution of 79 Hz were successfully obtained, which is reduced by one order of the linewidth, and increased by 56 times in frequency resolution compared to that excited by an electron spin. The integrated high-permeability MFC was designed to magnify the magnetic field near the diamond, with a magnification of 9.63 times. Then, the multi-frequency modulation technique was used to fully excite the hyperfine energy level of Nitrogen Vacancy (NV) centers along the four axes on the diamond with MFC, and magnetic detection sensitivity of 250pT/Hz1/2 was realized. These techniques should allow designing an integrated NV magnetometer with high sensitivity in a small volume.

Hybrid Quantum Systems with Artificial Atoms in Solid State

“…Magnetic Flux Concentrators (MFCs) NV centers in diamond membranes [98,99,[158][159][160] and nanodiamonds [101] have been combined with high-permeability magnetic flux concentrators (MFCs) to enhance their magnetic field sensitivity by collecting and focusing the magnetic field onto the sensor (see Figure 4a). With the MFCs capable of magnifying the field by a factor of >100, sensitivities for ensemble NV centers in diamond membranes have reached 195 fT/ √ Hz [98] and 90 pT/ √ Hz [99] for scalar and vector magnetometry, respectively.…”

High-Dynamic-Range Integrated NV Magnetometers

“…The external magnetic field applied to the NV axis can be determined by measuring the frequency shift of the resonance peaks in the optically detected magnetic resonance (ODMR) spectrum. The relationship between the frequency shift induced by the Zeeman splitting and the applied external magnetic field intensity is given by Equation (1) [34].…”