Cavity resonances in finite plasmonic chains

The authors report on the observation of cavity resonances along finite gold nanoparticle chains which, unlike continuous gold nanowires, lead to a high field concentration at their extremity. The mode signature has been assessed by probing the local field bound to the metal with two-photon luminescence spectroscopy. Simulations based on the Green dyadic method corroborate a good agreement with the measurements and bring further insight to the physics involved. (c) 2007 American Institute of Physics.