High-resolution spectroscopy of a single nitrogen-vacancy defect at zero magnetic field

TL;DR

This paper presents high-resolution microwave spectroscopy of single nitrogen-vacancy centers in diamond at zero magnetic field, revealing hyperfine transition features and developing a theoretical model for transition strengths under various microwave polarizations.

Contribution

It introduces a detailed experimental and theoretical analysis of hyperfine transitions in NV centers at zero field, aiding polarization-selective microwave excitation.

Findings

Observation of characteristic hyperfine transition splitting and imbalance.

Development of a theoretical model for transition strengths with arbitrary microwave polarization.

Identification of conditions for optimal polarization-selective excitation.

Abstract

We report a study of high-resolution microwave spectroscopy of nitrogen-vacancy centers in diamond crystals at and around zero magnetic field. We observe characteristic splitting and transition imbalance of the hyperfine transitions, which originate from level anti-crossings in the presence of a transverse effective field. We use pulsed electron spin resonance spectroscopy to measure the zero-field spectral features of single nitrogen-vacancy centers for clearly resolving such level anti-crossings. To quantitatively analyze the magnetic resonance behavior of the hyperfine spin transitions in the presence of the effective field, we present a theoretical model, which describes the transition strengths under the action of an arbitrarily polarized microwave magnetic field. Our results are of importance for the optimization of the experimental conditions for the polarization-selective microwave excitation of spin-1 systems in zero or weak magnetic fields.