Topological quantum dots: a novel platform for THz lasing quantum optics

Topological insulators (TIs) are a distinctive class of materials, which are insulating in the bulk but support topologically protected conducting surface states. Since their discovery, most work on these materials has focused on their electronic properties, whilst their interaction with electromagnetic fields has largely been untouched. In small topological insulator nanoparticles (TINPs) the dispersion relation of the topological surface states is no longer continuous but discretized. This system forms a type of topological quantum dot. By studying the optical transition properties between the states of the topological quantum dot we explore their use as a lasing system. The optical properties of the particle can be tuned by varying particle size, light frequency, and light polarization, providing a toolbox for quantum optics and quantum information technologies.