Sarah's PhD looks at solid-state entangled photon sources based on silicon-carbide.
Sources of entangled photon states are a key resource for quantum information processing. Current technologies for producing entangled photons employ complex experimental set ups or the use of spontaneous parametric down-conversion. For stable operation, the former requires low temperatures, often with vacuum environments, while the latter necessitates room temperatures but with low efficiencies. A recent breakthrough, however, has shown that artificial atomic systems based on silicon-carbide have the potential for significantly improving entangled photon pairs sources.
Silicon-carbide is a well-known semiconductor material with outstanding optical and electrical properties. Crystal defects in silicon-carbide produce discrete energy transitions for electrons which can lead to stable spontaneous emission of photons, even at room-temperature. In this project, Sarah will demonstrate the efficient generation of entangled photons from silicon-carbide. Due to the large bandgap available in silicon-carbide, it will be possible to develop sources emitting entangled photon states with different wavelengths, including telecommunication wavelengths (1330-1550nm). These silicon-carbide sources will be combined with cavities in order to improve entangled photon emission and collection. She aims to characterise these sources using modern methods in quantum optics and quantum information. Finally, Sarah will employ these sources to demonstrate quantum computing algorithms and quantum communication protocols.