title: Laser induced enhancement of dichroism in supported silver nanoparticles deposited by evaporation at glancing angles.
abstract: Silver nanoparticles (NPs) depicting well defined surface plasmon resonance (SPR) absorption were deposited on flat substrates by physical vapor deposition in a glancing angle configuration. The particles were characterized by scanning electron microscopy and atomic force microscopy and their optical properties examined by UV-vis absorption spectroscopy using linearly polarized light. It was found that, depending on the amount of deposited silver and the evaporation angle, part of the 'as-prepared' samples present NPs characterized by an anisotropic shape and a polarization dependent SPR absorption and different colors when using polarized white light at 0° and 90°. Low-power irradiation of these materials with an infrared Nd-YAG nanosecond laser in ambient conditions produced an enhancement in such dichroism. At higher powers, the dichroism was lost and the SPR bands shifted to lower wavelengths as a result of the reshaping of the silver NPs in the form of spheres. The possible factors contributing to the observed changes in dichroism are discussed.
authors.affiliation: Nanotechnology on Surfaces Laboratory, Materials Science Institute of Seville (ICMSE, CSIC-US), C/Americo Vespucio 49, 41092 Seville, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Nicolas Filippin
authors.forename: Ana
authors.initials: A
authors.lastname: Borras
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Rico
authors.forename: Fabian
authors.initials: F
authors.lastname: Frutos
authors.forename: Agustin R
authors.initials: AR
authors.lastname: González-Elipe
mesh_terms: D002942:Circular Dichroism / Q000379:methods*; D003460:Crystallization / Q000379:methods*; D007834:Lasers; D008027:Light; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties
chemical_list: D012834:Silver