Chip-integrated plasmonic cavity-enhanced single nitrogen-vacancy center emission

High temporal stability and spin dynamics of individual nitrogen-vacancy (NV) centers in diamond crystals
make them one of the most promising quantum emitters operating at room temperature. We demonstrate
a chip-integrated cavity-coupled emission into propagating surface plasmon polariton (SPP) modes
narrowing the NV center’s broad emission bandwidth with enhanced coupling efficiency. The cavity resonator
consists of two distributed Bragg mirrors that are built at opposite sides of the coupled NV emitter
and are integrated with a dielectric-loaded SPP waveguide (DLSPPW), using electron-beam lithography of
hydrogen silsesquioxane resist deposited on silver-coated silicon substrates. A quality factor of ∼70 for
the cavity (full width at half maximum ∼10 nm) with full tunability of the resonance wavelength is demonstrated.
An up to 42-fold decay rate enhancement of the spontaneous emission at the cavity resonance is
achieved, indicating high DLSPPW mode confinement