Stark Tuning and Electrical Charge State Control of Single Divacancies in Silicon Carbide

TL;DR

This paper demonstrates electric field tuning of optical frequencies and charge states of single divacancies in silicon carbide, enhancing their potential for quantum communication applications.

Contribution

It introduces a method to electrically tune and stabilize the charge state of divacancies in SiC, improving their optical properties for quantum technologies.

Findings

Electric fields can tune optical transitions over several GHz via the Stark effect.

Charge state control can be achieved on microsecond timescales.

Near-unity efficiency in preparing the neutral charge state using fluorescence detection.

Abstract

Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color centers whose long coherence times and near-telecom operating wavelengths make them promising for scalable quantum communication technologies compatible with existing fiber optic networks. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects, and hinders their coupling to optical cavities. Here we show that electric fields can be used to tune the optical transition frequencies of single neutral divacancy defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same technique can also control the charge state of the defect on microsecond timescales, which we use to stabilize unstable or non-neutral divacancies into their neutral charge state. Using fluorescence-based charge state detection, we show both 975 nm and 1130 nm excitation can prepare its neutral charge state with near unity efficiency.