  Solid state quantum emitters are a prime candidate in distributed quantum
technologies since they inherently provide a spin-photon interface. An ongoing
challenge in the field, however, is the low photon extraction due to the high
refractive index of typical host materials. This challenge can be overcome
using photonic structures. Here, we report the integration of V2 centers in a
cavity-based optical antenna. The structure consists of a silver-coated, 135 nm
thin 4H-SiC membrane functioning as a planar cavity with a broadband resonance
yielding a theoretical photon collection enhancement factor of 34. The planar
geometry allows us to identify over 20 single V2 centers at room temperature
with a mean (maximum) count rate enhancement factor of 9 (15). Moreover, we
observe 10 V2 centers with a mean absorption linewidth below 80MHz at cryogenic
temperatures. These results demonstrate a photon collection enhancement that is
robust to the lateral emitter position.
