Radiation Characteristics and Beam Forming of Multi-Particle Nanoantennas at Optical Frequencies

Owing to their ability to manipulate electromagnetic and optical radiation in sub-wavelength domains, plasmonic materials (such as silver and gold in the IR and optical frequencies) have attracted a great deal of interest in recent years (see e.g., [1]). One of the interesting structures is the plasmonic nanoparticles with a sub-wavelength size. When the dimension of the particles is much smaller than the operating wavelength, under the optical excitation they behave as induced dipoles which can exhibit large values at plasmonic resonance. Such a feature was suggested to be exploited for modifying the life time of a radiating dipole, mainly in the context of fluorescence (see e.g., [2]). However, to the best of our knowledge, less attention has been paid to the pattern synthesis and directivity control of a dipole when a collection of resonant plasmonic nanoparticles are placed in various locations in the vicinity of such a source. Recently, we began exploring such pattern syntheses and we presented our preliminary results in a recent symposium [3].