Practical applications of quantum sensing: a simple method to enhance sensitivity of Nitrogen-Vacancy-based temperature sensors

TL;DR

This paper introduces a simple, continuous-wave lock-in technique for nitrogen-vacancy-based temperature sensors that significantly improves sensitivity and reduces environmental magnetic noise interference at micro/nanoscale volumes.

Contribution

A novel continuous-wave lock-in method that enhances sensitivity and noise immunity in NV-center temperature sensing applications.

Findings

Achieved temperature sensitivity of 4.8 mK/Hz$^{1/2}$ in micro/nanoscale volumes.

Method is insensitive to environmental magnetic noise.

Provides a simple and effective approach for practical quantum sensing applications.

Abstract

Nitrogen-vacancy centers in diamond allow measurement of environment properties such as temperature, magnetic and electric fields at nanoscale level, of utmost relevance for several research fields, ranging from nanotechnologies to bio-sensing. The working principle is based on the measurement of the resonance frequency shift of a single nitrogen-vacancy center (or an ensemble of them), usually detected by by monitoring the center photoluminescence emission intensity. Albeit several schemes have already been proposed, the search for the simplest and most effective one is of key relevance for real applications. Here we present a new continuous-wave lock-in based technique able to reach unprecedented sensitivity in temperature measurement at micro/nanoscale volumes (4.8 mK/Hz$^{1/2}$ in $\mu$m$^3$). Furthermore, the present method has the advantage of being insensitive to the enviromental magnetic noise, that in general introduces a bias in the temperature measurement.