  The efficient interaction of light with quantum emitters is crucial to most
applications in nano and quantum photonics, such as sensing or quantum
information processing. Effective excitation and photon extraction are
particularly important for the weak signals emitted by a single atom or
molecule. Recent works have introduced novel collection strategies, which
demonstrate that large efficiencies can be achieved by either planar dielectric
antennas combined with high numerical-aperture objectives or optical
nanostructures that beam emission into a narrow angular distribution. However,
the first approach requires the use of elaborate collection optics, while the
latter is based on accurate positioning of the quantum emitter near complex
nanoscale architectures; hence, sophisticated fabrication and experimental
capabilities are needed. Here, we present a theoretical and experimental
demonstration of a planar optical antenna that beams light emitted by a single
molecule, which results in increased collection efficiency at small angles
without stringent requirements on the emitter position. The proposed device
exhibits broadband performance and is spectrally scalable, and it is simple to
fabricate and therefore applies to a wide range of quantum emitters. Our design
finds immediate application in spectroscopy, quantum optics and sensing.
