Background of the action
Novel and more sophisticated technologies that exploit the laws of quantum physics form a cornerstone for the future well-being, economic growth and security of Europe. Here photonic devices have gained a prominent position because the absorption, emission, propagation or storage of a photon is a process that can be harnessed at a fundamental level. However, the interaction of light with single quantum systems under ambient conditions is typically very weak and difficult to control in the solid state. Furthermore, there are quantum phenomena occurring in matter at nanometer length- and femtosecond time-scales that are currently not well understood. These deficiencies have a direct and severe impact on creating a bridge between quantum physics and photonic devices. Nano-optics and nanophotonics precisely address the issue of controlling the interaction between few photons and tiny amounts of matter and the ability to efficiently funnel them down to nanoscale volumes. Several research efforts funded by national and EU projects in the last decades resulted into enormous progress in quantum physics and quantum optics, on the one hand, and in nano-optics and nanophotonics, on the other hand. The COST Action Nanoscale Quantum Optics is the instrument to proactively increase the interaction among the communities of nanophotonics, quantum optics and materials science and to support them towards common objectives. The grand vision is the development of new ideas, materials, and techniques to control the interaction between light and matter at will, even down to the level of individual quanta. The potential breakthroughs will have profound implications in fields as diverse as classical and quantum information processing & communication, sensing & metrology, light sources, and energy harvesting.