Array of planar plasmonic scatterers functioning as light concentrator.

In this Letter, the concept of transmit array antenna enabling light concentration in the near-IR region is explored. As for the elements of the transmit array, concentric loop scatterers are chosen due to their design flexibility and potential for providing high phase variation by changing the dimensions of the loops. Periodic behaviors of the concentric loop elements are obtained by means of the finite-difference time-domain method. Using these results, a transmit array configuration is designed, and a focused beam at a desired distance is achieved. To model the electromagnetic fields of the finite array, the field equivalence principle and proper dyadic Green's functions are applied.