title: Magnetic polarization in the optical absorption of metallic nanoparticles.
abstract: We find remarkably strong absorption due to magnetic polarization in common colloidal and lithographic metallic nanoparticles. Our analysis is based upon a thorough examination of the dipolar electric and magnetic polarizabilities for representative combinations of nanoparticle composition, size, and morphology. We illustrate this concept by first discussing absorption in metallic spheres and then exploring ellipsoids, disks, and rings. Magnetic polarization reaches ~ 90% of the total absorption in 100 nm disks and rings for wavelengths above 1 μm under co-linear electric and magnetic irradiation. Our results demonstrate that the magnetic contribution to absorption cannot be naively overlooked, as it can largely exceed the contribution of electric polarization.
authors.affiliation: Instituto de Qu´ımica F´ısica Rocasolano - CSIC, Serrano 119, 28006 Madrid, Spain. ana.asenjo@csic.es
authors.forename: A
authors.initials: A
authors.lastname: Asenjo-Garcia
authors.forename: A
authors.initials: A
authors.lastname: Manjavacas
authors.forename: V
authors.initials: V
authors.lastname: Myroshnychenko
authors.forename: F J
authors.initials: FJ
authors.lastname: García de Abajo
mesh_terms: D000042:Absorption; D003198:Computer Simulation; D008027:Light; D060526:Magnetic Fields; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008956:Models, Chemical