Single telecom-wavelength vanadium quantum emitters in SiC with ultra-narrow inhomogeneous broadening*

Spin-photon interfaces associated with quantum emitters have shown great promise in quantum technologies, but a key limitation is a wide spread in optical emission frequencies, often spanning tens of GHz. In this talk, I will describe our work on telecom-ready single V4+ vanadium centres in 4H-SiC. By optical spectroscopy on individual emitters, we demonstrated for the first time spin-dependent optical transitions. By carefully engineering the SiC matrix's isotopic composition, we demonstrate a narrowing of the inhomogeneous spectral distribution among different emitters to a mere 100 MHz—considerably smaller than other single quantum emitters reported in the literature. These findings enhance the potential of single V emitters in SiC as material nodes for scalable telecom quantum networks.