Nitrogen vacancy center in diamond-based Faraday magnetometer

TL;DR

This paper presents a novel diamond-based Faraday magnetometer utilizing nitrogen vacancy centers, demonstrating room-temperature spin-state measurement and potential for femtotesla sensitivity with improved techniques.

Contribution

It introduces a new magnetometry method using a single laser beam and Faraday effect to measure NV center spin states at room temperature.

Findings

Sensitivity of 350 nT/√Hz achieved

Confirmed spin-orbit coupling in NV centers

Potential for femtotesla sensitivity with enhancements

Abstract

The nitrogen vacancy (NV) center in diamond is a versatile color center used for magnetometry, quantum computing, and quantum communications. In this article, using a single laser beam as a pump and probe, we measure the spin states of the NV center using the Faraday effect and use such measurements to develop a novel magnetic field sensor. Using the spin-state-dependent effect on the left and right circularly polarized light, we probe and confirm the existence of spin-orbit coupling in the NV center at room temperature. The sensitivity of our magnetometer is $350~$nT/$\sqrt{Hz}$, limited by the background produced by the laser trapped inside the diamond. We argue that by using an optical cavity and a high-purity diamond, sensitivities in the femtotesla level can be achieved.