title: Near- and Far-Field Optical Response of Eccentric Nanoshells.
abstract: We study the optical response of eccentric nanoshells (i.e., spherical nanoparticles with an eccentric spherical inclusion) in the near and the far field through finite-difference time-domain simulations. Plasmon hybridization theory is used to explain the obtained results. The eccentricity generates a far-field optical spectrum with various plasmon peaks. The number, position, and width of the peaks depend on the core offset. Near-field enhancements in the surroundings of these structures are significantly larger than those obtained for equivalent concentric nanoshells and, more importantly, they are almost independent of the illumination conditions. This opens up the door for using eccentric nanoshells in applications requiring intense near-field enhancements.
authors.affiliation: Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, E-28006, Madrid, Spain. ovidio@bytesfall.com.
authors.forename: Ovidio
authors.initials: O
authors.lastname: Peña-Rodríguez
authors.affiliation: Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, E-28006, Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Díaz-Núñez
authors.affiliation: Universidad Autónoma del Carmen, C/ 56 No. 4 Esq. Avenida Concordia, 24180, Ciudad del Carmen, Campeche, Mexico.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Rodríguez-Iglesias
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Apartado Postal J-48, 72570, Puebla, Puebla, Mexico.
authors.forename: Luis
authors.initials: L
authors.lastname: Montaño-Priede
authors.affiliation: Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, C/ José Gutiérrez Abascal 2, E-28006, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rivera
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Apartado Postal J-48, 72570, Puebla, Puebla, Mexico.
authors.forename: Umapada
authors.initials: U
authors.lastname: Pal
keywords: Eccentric nanoshells; FDTD method; Plasmon hybridization