  We demonstrate an approach, based on plasmonic apertures and gratings, to
enhance the radiative decay rate of single NV centers in diamond, while
simultaneously improving their collection efficiency. Our structures are based
on metallic resonators formed by surrounding sub-wavelength diamond nanoposts
with a silver film, which can enhance the spontaneous emission rate of an
embedded NV center. However, the collection efficiency of emitted photons
remains low due to losses to surface plasmons and reflections at the
diamond-air interface. In this work, we mitigate photon losses into these
channels by incorporating grating structures into the plasmonic cavity system.
