title: Self-similar gold-nanoparticle antennas for a cascaded enhancement of the optical field.
abstract: We experimentally demonstrate cascaded field enhancement by means of gold nanoparticle dimer and trimer antennas. The local field enhancement is probed by single-molecule fluorescence using fluorophores with high intrinsic quantum efficiency (Q(0)>80%). Using a self-similar trimer antenna consisting of 80, 40, and 20 nm gold nanoparticles, we demonstrate a fluorescence enhancement of 40 and a spatial confinement of 15 nm. Compared with a single gold nanoparticle, the self-similar trimer antenna improves the enhancement-confinement ratio by more than an order of magnitude. Self-similar antennas hold promise for high-resolution imaging and spectroscopy, ultrasensitive detection, and efficient single-photon sources.
authors.affiliation: Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Christiane
authors.initials: C
authors.lastname: Höppener
authors.forename: Zachary J
authors.initials: ZJ
authors.lastname: Lapin
authors.forename: Palash
authors.initials: P
authors.lastname: Bharadwaj
authors.forename: Lukas
authors.initials: L
authors.lastname: Novotny
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000295:instrumentation* / Q000379:methods*; D010078:Oxazines / Q000737:chemistry; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D010078:Oxazines; C008619:Nile Blue; D006046:Gold