Coherence properties and quantum control of silicon vacancy color centers in diamond
Atomic-scale impurity spins, also called color centers, in an otherwise spin-free diamond host lattice have proven to be versatile tools for applications in solid-state-based quantum technologies ranging from quantum information processing (QIP) to quantum-enhanced sensing and metrology. Due to its wide band gap, diamond can host hundreds of different color centers. However, their suitability for QIP or sensing applications has only been tested for a handful of these, with the nitrogen vacancy (NV) strongly dominating this field of research. Due to its limited optical properties, the success of the NV for QIP applications however strongly depends on the development of efficient photonic interfaces. In the past years the negatively charged silicon vacancy (SiV) center received significant attention due to its highly favourable spectral properties such as narrow zero phonon line transitions and weak phonon sidebands. We here review recent work investigating the SiV centre's orbital and electron spin coherence properties as well as techniques to coherently control its quantum state using microwave as well as optical fields and we outline potential future experimental directions to improve the SiV's coherence time scale and to develop it into a valuable tool for QIP applications.