Multiple Plasmonic Resonances and Cascade Effect in Asymmetrical Ag Nanowire Homotrimer

Plasmonic Ag nanowire homotrimer with asymmetrical radii and separations, which exhibits characteristics of multiple plamonic resonances and different electric fleld distributions, is systematically investigated by means of 2D flnite element method. It was found that the dark and bright modes appear in asymmetrical nanowire homotrimer. In addition, when the dark modes appear between the smaller radii of the nanowires, the cascade effect results in enhanced electric fleld between the smaller radii nanowires. As a result of the appearance of the bright modes between the smaller radii of the nanowires, the restriction of the cascade effect generates enhanced electric fleld between the bigger nanowires.