Current state of knowledge

State-of-the-art efforts currently concentrate on four general themes:
The development of novel materials (e.g. graphene, silicene, metamaterials) and optical devices (plasmonic structures, nanofibers, photonic crystals, optomechanical systems, superconducting detectors) that can facilitate and control strong quantum light-matter interactions, and the advance of novel experimental methods that enable quantum degrees of freedom (colour centres in solids, quantum dots, ions, molecules, neutral atoms) to be interfaced with these systems. Prominent efforts include:

  • Quantum dot devices to generate single and entangled pairs of photons on demand.
  • Novel devices such as nanoscale resonant structures, plasmonic waveguides or nanofibres to achieve efficient coupling of single photons.
  • Novel fabrication techniques for diamond-based photonics, which can be used to enhance optical coupling to individual defect colour centres (such as the nitrogen vacancy (NV)).
  • Methods to trap cold neutral atoms to nanophotonic systems, such as tapered optical fibres, thus enabling a coherent atom-nanophotonics quantum interface.
  • Metamaterials and graphene plasmonics are being actively explored as new platforms to channel light and control their interactions with quantum systems.
  • The development of switches that operate at few photon levels could drastically mitigate the high energy required for optical communication and computation in supercomputers and it will also play a major role in the reduction of worldwide energy requirements in ICT technologies.
  • Bio-inspired materials such as light-harvesting complexes could open new routes towards efficient photovoltaic cells.
  • New approaches to single-molecule detection and quantum-enhanced measurements will expand sensor capabilities opening new scenarios particularly within the fields of metrology, security and safety.