Check-probe spectroscopy of lifetime-limited emitters in bulk-grown silicon carbide

TL;DR

This paper introduces a high-bandwidth check-probe spectroscopy method to measure spectral diffusion and coherence in single emitters in silicon carbide, demonstrating near-lifetime-limited optical coherence despite spectral diffusion.

Contribution

The study presents a novel check-probe spectroscopy scheme for quantifying spectral diffusion and coherence in bulk-grown silicon carbide emitters, showing their potential for quantum technology applications.

Findings

Optical transitions are narrow (~35 MHz) and stable in the dark for over 1 second.

Spectral diffusion occurs at rates exceeding GHz per second under laser illumination.

Optical coherence is near the lifetime limit with T2 approximately 16.4 ns.

Abstract

Solid-state single-photon emitters provide a versatile platform for exploring quantum technologies such as optically connected quantum networks. A key challenge is to ensure optical coherence and spectral stability of the emitters. Here, we introduce a high-bandwidth `check-probe' scheme to quantitatively measure (laser-induced) spectral diffusion and ionisation rates, as well as homogeneous linewidths. We demonstrate these methods on single V2 centers in commercially available bulk-grown 4H-silicon carbide. Despite observing significant spectral diffusion under laser illumination ($\gtrsim$ GHz/s), the optical transitions are narrow ($\sim$35 MHz), and remain stable in the dark ($\gtrsim$1 s). Through Landau-Zener-St\"uckelberg interferometry, we determine the optical coherence to be near-lifetime limited ($T_2 = 16.4(4)$ ns), hinting at the potential for using bulk-grown materials for developing quantum technologies. These results advance our understanding of spectral diffusion of quantum emitters in semiconductor materials, and may have applications for studying charge dynamics across other platforms.