# Vector magnetic field sensing via multi-frequency control of nitrogen-vacancy centers in diamond

## TL;DR

This paper introduces a multi-frequency control method for nitrogen-vacancy centers in diamond to enhance the sensitivity of vector magnetic field sensing by increasing readout contrast through parallel control of different NV center orientations.

## Contribution

It proposes a novel multi-frequency microwave control scheme that allows independent manipulation of NV centers along different axes, improving vector magnetic field detection sensitivity.

## Key findings

- Enhanced readout contrast in NV-based magnetic sensing
- Parallel control of four NV center orientations
- Potential for practical diamond-based vector field sensors

## Abstract

An ensemble of nitrogen-vacancy (NV) centers in diamond is an attractive device to detect small magnetic fields. In particular, by exploiting the fact that the NV center can be aligned along one of four different axes due to symmetry, it is possible to extract information concerning vector magnetic fields. However, in the conventional scheme, low readout contrasts of the NV centers significantly decrease the sensitivity of the vector magnetic field sensing. Here, we propose a way to improve the sensitivity of the vector magnetic field sensing of the NV centers using multi-frequency control. Since the Zeeman energy of the NV centers depends on the direction of the axis, we can independently control the four types of NV centers using microwave pulses with different frequencies. This allows us to use every NV center for the vector field detection in parallel, which effectively increases the readout contrast. Our results pave the way to realize a practical diamond-based vector field sensor.