Ultra-narrow inhomogeneous spectral distribution of telecom-wavelength vanadium centres in isotopically-enriched silicon carbide

TL;DR

This paper demonstrates that by engineering isotopic composition and dopant concentration in silicon carbide, the spectral inhomogeneity of vanadium-based quantum emitters at telecom wavelengths can be significantly reduced, enhancing their suitability for quantum networks.

Contribution

The study introduces a method to narrow the spectral distribution of vanadium centers in SiC to 100 MHz and stabilizes their charge state, advancing quantum emitter technology.

Findings

Spectral distribution reduced to 100 MHz

Charge state stabilized, extending lifetime by 100x

Observation of spin-dependent optical transitions

Abstract

Spin-active quantum emitters have emerged as a leading platform for quantum technologies. However, one of their major limitations is the large spread in optical emission frequencies, which typically extends over tens of GHz. Here, we investigate single V4+ vanadium centres in 4H-SiC, which feature telecom-wavelength emission and a coherent S=1/2 spin state. We perform spectroscopy on single emitters and report the observation of spin-dependent optical transitions, a key requirement for spin-photon interfaces. By engineering the isotopic composition of the SiC matrix, we reduce the inhomogeneous spectral distribution of different emitters down to 100 MHz, significantly smaller than any other single quantum emitter. Additionally, we tailor the dopant concentration to stabilise the telecom-wavelength V4+ charge state, thereby extending its lifetime by at least two orders of magnitude. These results bolster the prospects for single V emitters in SiC as material nodes in scalable telecom quantum networks.