title: Broadband converging plasmon resonance at a conical nanotip.
abstract: We propose an analytical theory which predicts that Converging Plasmon Resonance (CPR) at conical nanotips exhibits a red-shifted and continuous band of resonant frequencies and suggests potential application of conical nanotips in various fields, such as plasmonic solar cells, photothermal therapy, tip-enhanced Raman and other spectroscopies. The CPR modes exhibit superior confinement and ten times broader scattering bandwidth over the entire solar spectrum than smooth nano-structures. The theory also explicitly connects the optimal angles and resonant optical frequencies to the material permittivities, with a specific optimum half angle that depends only on the real permittivity for high-permittivity and low-loss materials.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Notre Dame,Notre Dame, Indiana 46556, USA.
authors.forename: Yunshan
authors.initials: Y
authors.lastname: Wang
authors.forename: Franck
authors.initials: F
authors.lastname: Plouraboue
authors.forename: Hsueh-Chia
authors.initials: HC
authors.lastname: Chang
mesh_terms: D003198:Computer Simulation; D006046:Gold / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D020349:Surface Plasmon Resonance
chemical_list: D006046:Gold