Hyperbolic Meta-Antennas Enable Full Control of Scattering and Absorption of Light

We show that plasmonic nanopillars made of a composite material displaying a type II hyperbolic dispersion enable precise and controlled spectral separation of absorption and scattering processes in the visible/near-infrared frequency range. The experimental evidence is supported by a comprehensive theoretical study. We demonstrate that the physical mechanism responsible for the aforementioned effect lies on the different natures of the plasmonic modes excited within the hyperbolic nanopillars. We prove that it is possible to have a pure scattering channel if an electric dipolar mode is induced, while a pure absorption process can be obtained if a magnetic dipole is excited within the nanopillars. Also, by varying the geometry of the system, the relative weight of scattering vs absorption can be tuned, thus enabling an arbitrary control of the decay channels. Importantly, both modes can be efficiently excited by direct coupling with the far field radiation, even when the radiative channel (scattering) is almost totally suppressed, hence making the propose architecture suitable for practical applications.