Quantum dots are nanoscale semiconductor structures with unique properties that have long been heralded for their potential in various applications. They can also be used to trap excitons, which are bound electron-hole pairs formed when a material absorbs photons. A new approach to achieving electrical control of optically active quantum dots overcomes traditional limits on scalability and precision—enhancing prospects for the use of excitons and quantum dots in future cutting-edge applications such as photonic quantum computing. Interest in excitons relates to their inherent qualities. Unlike photons, these short-lived quasi-particles have electric charges, which makes them an attractive interface between electronics and photonics. In the few picoseconds before re-emerging as luminescence, excitons can be manipulated in distinctive ways, for instance, through the application of electrical fields. A team of scientists from NTT Research, the Swiss Federal Institute of Technology (ETH) Zürich, and Stanford University, co-led by me and ETH Professor Puneet Murthy, introduced a method not only for confining excitons electrically, but also for measuring and scaling them up through arrays of quantum dots and other geometries. Electrically controlled quantum dots unlock new possibilities | Laser Focus World