Optical Properties of Single Silicon Vacancies in 4H-SiC

Defect states in wide bandgap materials have generated substantial interest in the past twenty years as promising systems for quantum information and quantum sensing because of their optical and spin properties. Recent work has found many promising SiC defect states, and so, coupled with the rapid maturation of SiC processing technology, SiC has become an attractive material for potential photonic and spintronic applications. The silicon vacancies in 4H-SiC are particularly interesting defects for near-infrared quantum optics, and we focus on V2 defect, which shows long spin coherence times even at room temperature. While much work has been performed on characterizing the spin properties of this defect, there are still many unknowns concerning the optical properties, particularly for single defects. We present high-resolution optical spectroscopy of single defects to better understand their emission properties and energy level structure. We show that the optical linewidths are narrow and resolve the fine structure of the excited state, which has significant differences compared to other commonly studied defects. This refined understanding of the optical transitions paves the way for precision quantum optical control of spins and photons.