Optically Detected Magnetic Resonance of Nitrogen-Vacancy Centers in Diamond under Weak Laser Excitation

TL;DR

This study investigates how weak laser excitation affects the optically detected magnetic resonance of nitrogen-vacancy centers in diamond, revealing power-dependent spectral changes crucial for sensitive quantum sensing applications.

Contribution

It combines theoretical modeling and experimental validation to understand ODMR behavior of NV centers under weak laser excitation, highlighting charge neutralization effects.

Findings

ODMR spectral width and splitting decrease with increasing laser power

Charge neutralization of NV--N+ pairs influences local electric fields

Results inform design of NV-based sensors for light-sensitive environments

Abstract

As promising quantum sensors, nitrogen-vacancy (NV) centers in diamond have been widely used in frontier studies in condensed matter physics, material sciences, and life sciences. In practical applications, weak laser excitation is favorable as it reduces the side effects of laser irradiation, for example, phototoxicity and heating. Here we report a combined theoretical and experimental study of optically detected magnetic resonance (ODMR) of NV-center ensembles under weak 532-nm laser excitation. In this regime, both the width and splitting of ODMR spectra decrease with increasing laser power. This power dependence is reproduced with a model considering laser-induced charge neutralization of NV--N+ pairs, which alters the local electric field environment. These results are important for understanding and designing NV-based quantum sensing in light-sensitive applications.