There is provided an illumination device (100) comprising: a substrate (104); an optically transmissive first layer (106) arranged on the substrate; a photon emitting layer (108), arranged on the optically transmissive first layer and comprising a photon emitting material configured to receive energy from an energy source and to emit light having a predetermined wavelength; a periodic plasmonic antenna array, arranged on the substrate and embedded within the first layer, and comprising a plurality of individual antenna elements (114) arranged in an antenna array plane, the plasmonic antenna array being configured to support a first lattice resonance at the predetermined 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 photon emitting 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; and wherein the photon emitting layer is arranged at a distance from the antenna array plane corresponding to a location of maximum field enhancement for light out-coupling resulting from the plasmonic-photonic lattice resonances.