Jahn-Teller-induced femtosecond electronic depolarization dynamics of the nitrogen-vacancy defect in diamond.

Ronald Ulbricht,Keshav M. Dani,Shuo Dong,I-Ya Chang,Bala Murali Krishna Mariserla,Kim Hyeon-Deuk,Zhi-Heng Loh

doi:10.1038/ncomms13510

Abstract

Single-photon emission from the nitrogen-vacancy defect in diamond constitutes one of its many proposed applications. Owing to its doubly degenerate 3E electronic excited state, photons from this defect can be emitted by two optical transitions with perpendicular polarization. Previous measurements have indicated that orbital-selective photoexcitation does not, however, yield photoluminescence with well-defined polarizations, thus hinting at orbital-averaging dynamics even at cryogenic temperatures. Here we employ femtosecond polarization anisotropy spectroscopy to investigate the ultrafast electronic dynamics of the 3E state. We observe subpicosecond electronic dephasing dynamics even at cryogenic temperatures, up to five orders of magnitude faster than dephasing rates suggested by previous frequency- and time-domain measurements. Ab initio molecular dynamics simulations assign the ultrafast depolarization dynamics to nonadiabatic transitions and phonon-induced electronic dephasing between the two components of the 3E state. Our results provide an explanation for the ultrafast orbital averaging that exists even at cryogenic temperatures.

Highlights

Single-photon emission from the nitrogen-vacancy defect in diamond constitutes one of its many proposed applications
The positive DT/T signal on the red side of the zero-phonon line (ZPL) is because of Stokes-shifted stimulated emission from the v0 1⁄4 0 level of the 3E state, populated by the pump pulse, to the various n00 levels on the 3A2 ground state. The former signal is sensitive to ground-state dynamics, whereas the latter is sensitive to excited state dynamics
Previous frequency- and time-domain measurements were performed on high-purity Type 2a diamond samples, which have defect densities that are in the parts-per-billion (p.p.b.) regime, and orders of magnitude lower than the Type 1b sample (B100 p.p.m.) used in the present study

Summary

Introduction

Single-photon emission from the nitrogen-vacancy defect in diamond constitutes one of its many proposed applications. Among the known colour centres of diamond, the negatively charged nitrogen-vacancy (NV À ) defect has attracted the most attention[1], motivated by its potential to serve as a building block for novel quantum technologies Remarkable advances in their magnetic and optical manipulation, performed even at the single-defect level[2], herald their application to spin-based quantum computing[3,4] and photonics[5], as well as nanoscale magnetic field[6,7,8] and temperature sensors[9,10,11]. Buried deep within the band gap of diamond are the NV À 3A2 electronic ground state and the doubly degenerate 3E excited state, which are optically coupled by a narrow zero-phonon line (ZPL) transition at 1.95 eV (637 nm wavelength, Fig. 1a) This optical transition has been identified as a potential quantum emitter for single photons[1,5]. For the NV– defect, the theoretically predicted JT stabilization energy EJT of 25 meV is smaller than the tunnelling splitting of 34 meV, rendering the system a dynamic JT distortion[13]

Methods

Results

Conclusion