Tunable nanoscale localization of energy on plasmon particle arrays

We demonstrate experimentally that plasmon resonant nanoparticle chains exhibit a nanoscale localized response to unfocused light that can be controlled by tuning the incident wavelength. Confocal microscopy shows that field concentrates on just a few nanoparticles at either the front or back side of the plasmon chains. Our experiments clearly demonstrate that plasmon chains are nanoscale receivers and concentrators of light analogous to multielement radio wave antennas. This analogy inspires new design rules for many other photonic functionalities, like guiding and redirecting light at the nanoscale.