  We demonstrate that a periodic array of optical antennas sustains a resonant
Near-Field (NF) and an anti-resonant Far-Field (FF) at the same energy and
in-plane momentum. This phenomenon arises in the context of coupled plasmonic
lattice resonances, whose bright and dark character is interchanged at a
critical antenna length. The energies of these modes anti-cross in the FF, but
cross in the NF. Hence, we observe an extremely narrow bandwidth emission
enhancement from quantum dots in the proximity of the array, while the antennas
scatter minimally into the FF. Simulations reveal that a standing wave with a
quadrupolar field distribution is the origin of this dark collective resonance.
