Voltage-Tunable Nonlocal Metasurface for Enhanced Outcoupling of Emission from Quantum Dots.

Cooperative emission of indistinguishable photons from multiple distant sources can enable quantum information processing, and low-density semiconductor quantum dots (QDs) embedded in metasurfaces hold promise to scale up this functionality. However, the inhomogeneity in size within QD ensembles and limited interresonator coupling in local metasurfaces make this effect highly unlikely. Here, we demonstrate a nonlocal metasurface platform with embedded GaAs QDs coupled to extended photonic modes with emission wavelength tunability and enhanced free-space emission outcoupling. Natural variation in the QD dipole moment allows us to tune two QDs into spectral alignment and resonance with selected modes. As a result, two distant QDs can produce same-wavelength photons with strongly improved outcoupling efficiency to free space. The nonlocal and periodic nature of the developed metasurface eliminates the need for precise placement of individual QDs and, although cooperative emission was not yet demonstrated, this metasurface platform opens doors for investigations of cooperative effects for quantum information system applications.