Temperature dependent coherence properties of NV ensemble in diamond up to 600K

TL;DR

This study investigates how the coherence properties of NV centers in diamond change from 300 K to 600 K, revealing temperature-dependent decoherence mechanisms and demonstrating a high-temperature thermal-echo thermometer.

Contribution

It provides the first systematic analysis of NV ensemble coherence at high temperatures up to 600 K, highlighting the dominant phonon processes and potential for high-temperature sensing.

Findings

Coherence time T2 decreases from 184 μs to 30 μs as temperature increases.

Double-quantum relaxation rates are dominated by two phonon Raman processes.

Thermal-echo-based thermometer achieves 41 mK/√Hz sensitivity at 450 K.

Abstract

Nitrogen-vacancy (NV) center in diamond is an ideal candidate for quantum sensors because of its excellent optical and coherence property. However, previous studies are usually conducted at low or room temperature. The lack of full knowledge of coherence properties of the NV center at high temperature limits NV's further applications. Here, we systematically explore the coherence properties of the NV center ensemble at temperatures from 300 K to 600 K. Coherence time $T_2$ decreases rapidly from $184 \mu s$ at 300 K to $30 \mu s$ at 600 K, which is attributed to the interaction with paramagnetic impurities. Single-quantum and double-quantum relaxation rates show an obvious temperature-dependent behavior as well, and both of them are dominated by the two phonon Raman process. While the inhomogeneous dephasing time $T_2^*$ and thermal echo decoherence time $T_{TE}$ remain almost unchanged as temperature rises. Since $T_{TE}$ changed slightly as temperature rises, a thermal-echo-based thermometer is demonstrated to have a sensitivity of $41 mK/\sqrt{Hz}$ at 450 K. These findings will help to pave the way toward NV-based high-temperature sensing, as well as to have a more comprehensive understanding of the origin of decoherence in the solid-state qubit.