Broadband converging plasmon resonance at a conical nanotip

Yunshan Wang (1) , Franck Plouraboué (2) , Hsueh-Chia Chang (1)

1 Department of Chemical and Biomolecular Engineering (Notre Dame, USA)
2 IMFT - Institut de mécanique des fluides de Toulouse

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.

Mots clés: Surface plasmons; Subwavelength structures; Nanostructures; Solar energy; Photothermal effects

Domaines: Optique / photonique

Yunshan Wang, Franck Plouraboué, Hsueh-Chia Chang. Broadband converging plasmon resonance at a conical nanotip. Optics Express, 2013, vol. 21, pp.6609-6617. ⟨10.1364/OE.21.006609⟩. ⟨hal-00824640⟩