title: Second-harmonic generation from coupled plasmon modes in a single dimer of gold nanospheres.
abstract: We show that a dimer made of two gold nanospheres exhibits a remarkable efficiency for second-harmonic generation under femtosecond optical excitation. The detectable nonlinear emission for the given particle size and excitation wavelength arises when the two nanoparticles are as close as possible to contact, as in situ controlled and measured using the tip of an atomic force microscope. The excitation wavelength dependence of the second-harmonic signal supports a coupled plasmon resonance origin with radiation from the dimer gap. This nanometer-size light source might be used for high-resolution near-field optical microscopy.
authors.affiliation: Laboratoire de Photonique Quantique et Moléculaire, Ecole Normale Supérieure de Cachan and CNRS, UMR 8537, F-94235 Cachan Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Slablab
authors.forename: L
authors.initials: L
authors.lastname: Le Xuan
authors.forename: M
authors.initials: M
authors.lastname: Zielinski
authors.forename: Y
authors.initials: Y
authors.lastname: de Wilde
authors.forename: V
authors.initials: V
authors.lastname: Jacques
authors.forename: D
authors.initials: D
authors.lastname: Chauvat
authors.forename: J-F
authors.initials: JF
authors.lastname: Roch
mesh_terms: D019281:Dimerization; D006046:Gold / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D054118:Nanospheres / Q000737:chemistry* / Q000648:ultrastructure*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D006046:Gold