This theme centres on the interaction of single electrons and single photons. Such systems are essential building blocks for quantum information hardware, such as quantum memories and quantum gates. Experiments are performed on InAs-based quantum dots in micropillar cavities and on Rare Earth ions (in particular Yb) in optical ring cavities. The single-photon nonlinearities observed in the micropillar system enable the construction of a quantum CNOT gate with charged quantum dots and the generation of multi-partite entanglement with such devices. Parametric down-conversion is used as a tool to generate quantum-entangled photons and analyse their high-dimensional spatial entanglement both at the photon pair level and beyond.
A related research topic is symmetry breaking and topology in optics and plasma physics. Examples are how periodic structures can induce perfect optical absorption, even in thin films, and can create edge effects in photonic graphene. We study surface plasmon lasing in metal films with hole-array patterns with an adjacent semiconductor gain medium. In analogy with the predicted optical structures, we also investigate knotted and linked forms of plasma, forms that are expected to have exceptional stability and emerge naturally from plasma with initial helicity.