Monitoring Dark-State Dynamics of a Single Nitrogen-Vacancy Center in Nanodiamond by Auto-Correlation Spectroscopy: Photonionization and Recharging.

Jing Liu,Mengdi Zhang,Bai-Yan Li

doi:10.3390/nano11040979

Abstract

In this letter, the photon-induced charge conversion dynamics of a single Nitrogen-Vacancy (NV) center in nanodiamond between two charge states, negative (NV−) and neutral (NV0), is studied by the auto-correlation function. It is observed that the ionization of NV− converts to NV0, which is regarded as the dark state of the NV−, leading to fluorescence intermittency in single NV centers. A new method, based on the auto-correlation calculation of the time-course fluorescence intensity from NV centers, was developed to quantify the transition kinetics and yielded the calculation of transition rates from NV− to NV0 (ionization) and from NV0 to NV− (recharging). Based on our experimental investigation, we found that the NV−-NV0 transition is wavelength-dependent, and more frequent transitions were observed when short-wavelength illumination was used. From the analysis of the auto-correlation curve, it is found that the transition time of NV− to NV0 (ionization) is around 0.1 μs, but the transition time of NV0 to NV− (recharging) is around 20 ms. Power-dependent measurements reveal that the ionization rate increases linearly with the laser power, while the recharging rate has a quadratic increase with the laser power. This difference suggests that the ionization in the NV center is a one-photon process, while the recharging of NV0 to NV− is a two-photon process. This work, which offers theoretical and experimental explanations of the emission property of a single NV center, is expected to help the utilization of the NV center for quantum information science, quantum communication, and quantum bioimaging.

Highlights

A solid state non-classical light source, Nitrogen Vacancy (NV) centers in diamond have recently drawn unprecedented interest because of their unique spin states and remarkable single photon emission at room temperature [1,2]
This work introduces a simple approach to quantify the kinetics of ON/OFF transition with autocorrelation
Based on a model with triplet states, the analytical expression of the autocorrelation function is derived, and multiple parameters associated with the transition kinetics are extracted

Summary

Introduction

A solid state non-classical light source, Nitrogen Vacancy (NV) centers in diamond have recently drawn unprecedented interest because of their unique spin states and remarkable single photon emission at room temperature [1,2]. The intermittency of the fluorescence emission from a single NV center was observed under several different conditions, leaving the NV center in a “bright state” or a “dark state”. This “dark state” is usually eluded in encoding the quantum bit, the accuracy of which is deteriorated by the fluorescence jump and spectral diffusion of single photon emitters [15]; in addition, the “dark state” prevents efficient coupling between emitters and nano-cavities [16,17]. Just as a coin has two sides, the “dark state” is preferred in the super resolution imaging of nanodiamonds

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Conclusion