title: A microsphere coupler for a nanowire waveguide plasmonic probe for molecular imaging.
abstract: Highly forward scattering of light by a silica microsphere is predicted by Mie theory. Finite-difference time-domain simulations are used to examine the use of a silica microsphere for coupling light into a ZnO nanowire terminated with a gold nanoparticle (NP) tip, intended for near-field imaging of single molecules immobilized on a gold substrate or gold nanoparticle-labeled cell membranes. The results show that plasmonic coupling at the Au tip is dependent on the incident angle of the excitation. Pre-conditioning the signal with the microsphere amplifies the coupling while reducing background energy levels, significantly boosting the signal-to-noise ratio.
authors.affiliation: PC Krause and Associates, West Lafayette, IN 47906, USA. heltzel@pcka.com
authors.forename: Alex
authors.initials: A
authors.lastname: Heltzel
authors.forename: Li
authors.initials: L
authors.lastname: Shi
authors.forename: John R
authors.initials: JR
authors.lastname: Howell
mesh_terms: D015415:Biomarkers / Q000032:analysis; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D020527:Microscopy, Scanning Probe / Q000295:instrumentation*; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D006046:Gold; D015034:Zinc Oxide