High Resolution Temperature-Resolved Spectroscopy of the Nitrogen Vacancy $^{1}E$ Singlet State Ionization Energy

TL;DR

This study refines the ionization energy of the $ ext{^{1}E}$ singlet state in NV centers using high-resolution temperature-resolved spectroscopy, enhancing understanding crucial for quantum sensing applications.

Contribution

The paper introduces a detailed measurement of the $ ext{^{1}E}$ ionization energy across various wavelengths and temperatures, reducing uncertainty significantly compared to prior data.

Findings

Ionization energy of $ ext{^{1}E}$ is between 2.29 and 2.33 eV.

Temperature and wavelength dependence of the $ ext{^{1}E}$ state was characterized.

Enhanced precision in energy level determination for NV centers.

Abstract

The negatively charged diamond nitrogen-vacancy ($\mathrm{{NV}^-}$) center plays a central role in many cutting edge quantum sensing applications; despite this, much is still unknown about the energy levels in this system. The ionization energy of the $\mathrm{^{1}E}$ singlet state in the $\mathrm{{NV}^-}$ has only recently been measured at between 2.25 eV and 2.33 eV. In this work, we further refine this energy by measuring the $\mathrm{^{1}E}$ energy as a function of laser wavelength and diamond temperature via magnetically mediated spin-selective photoluminescence (PL) quenching; this PL quenching indicating at what wavelength ionization induces population transfer from the $\mathrm{^{1}E}$ into the neutral $\mathrm{{NV}^0}$ charge configuration. Measurements are performed for excitation wavelengths between 450 nm and 470 nm and between 540 nm and 566 nm in increments of 2 nm, and for temperatures ranging from about 50 K to 150 K in 5 K increments. We determine the $\mathrm{^{1}E}$ ionization energy to be between 2.29 and 2.33 eV, which provides about a two-fold reduction in uncertainty of this quantity. Distribution level: A. Approved for public release; distribution unlimited.