Tunable, directional and wavelength selective plasmonic nanoantenna arrays

Linear arrays of noble metal nanoparticles, supporting Bragg plasmonic resonances, are proposed as optical nanoantennae. Electrodynamic calculations show that tunable, directional and wavelength selective emission enhancement is obtained throughout the visible and near-infrared spectrum by varying the dielectric environment and the array geometrical parameters, and thus tuning the Bragg modes. Large quantum efficiency enhancements are possible even in the case of poor emitters (1% intrinsic efficiency), spanning wavelengths that are relevant in lighting (lambda approximately equal 400 nm) and telecommunication (lambda approximately equal 1.5 microm) applications. Nanoantenna array angular emission is highly directional and extremely sensitive to the array geometrical parameters and the dielectric environment.