US Patent 9995460 Solid state illumination device based on non-radiative energy transfer

There is provided an illumination device comprising: a wavelength converting layer comprising a photon emitting donor configured to absorb energy to reach an excited state, and a photon emitting acceptor; an energy source configured to provide energy to the donor such that the donor reach the excited state; wherein the donor and the acceptor are selected and arranged at a distance from each other such that non-radiative transfer of excitation energy from the donor to the acceptor occur, and wherein the acceptor is configured to emit a photon at a second wavelength after the transfer of energy; the illumination device further comprising a periodic plasmonic antenna array, arranged on the substrate and embedded within the wavelength converting layer, and comprising a plurality of individual antenna elements arranged in an antenna array plane, the plasmonic antenna array being configured to support a first lattice resonance at the second wavelength, arising from coupling of localized surface plasmon resonances in the individual antenna elements to photonic modes supported by the system comprising the plasmonic antenna array and the wavelength converting layer, wherein the plasmonic antenna array is configured to comprise plasmon resonance modes such that light emitted from the plasmonic antenna array has an anisotropic angle distribution.