%0 Journal Article %T Unidirectional and Wavelength Selective Photonic Sphere-Array Nanoantennas %A Yang G. Liu %A Wallace C. H. Choy %A Wei E. I. Sha %A Weng Cho Chew %J Physics %D 2015 %I arXiv %R 10.1364/OL.37.002112 %X We design a photonic sphere-array nanoantenna (NA) exhibiting both strong directionality and wavelength selectivity. Although the geometric configuration of the photonic NA resembles a plasmonic Yagi-Uda NA, it has different working principles, and most importantly, reduces the inherent metallic loss from plasmonic elements. For any selected optical wavelength, a sharp Fano-resonance by the reflector is tunable to overlap spectrally with a wider dipole resonance by the sphere-chain director leading to the high directionality. The work provides design principles for directional and selective photonic NAs, which is particularly useful for photon detection and spontaneous emission manipulation. %U http://arxiv.org/abs/1507.00086v1