Pyramidal Hyperbolic Metasurfaces Enhance Spontaneous Emission of Nitrogen-Vacancy Centers in Nanodiamond

摘要

Nitrogen-vacancy (NV) centers in nanodiamond hold great promise for creatingsuperior biological labels and quantum sensing methods. Yet, inefficientphoton generation and extraction from excited NV centers restrict the achievablesensitivity and temporal resolution. Herein, an entirely complementaryroute featuring pyramidal hyperbolic metasurface is reported to modify thespontaneous emission of NV centers. Fabricated using nanosphere lithography,the metasurface consists of alternatively stacked silica–silver thin filmsconfigured in a pyramidal fashion, and supports both spectrally broadbandPurcell enhancement and spatially extended intense local fields owing to thehyperbolic dispersion and plasmonic coupling. The enhanced photophysicalproperties are manifested as a simultaneous amplification to the spontaneousdecay rate and emission intensity of NV centers. It is envisioned thatthe reported pyramidal metasurface can serve as a versatile platform for creatingchip-based ultrafast single-photon sources and spin-enhanced quantumbiosensing strategies, as well as aid in further fundamental understanding ofphotoexcited species in condensed phases.