Optical Forces on Silver Homogeneous Nanotubes: Study of Shell Plasmonic Interaction

R. M. ABRAHAM EKEROTH; M. LESTER

PLASMONICS

SPRINGER

Lugar: Londres; Año: 2015

1557-1955

In previous works (Abraham et al., Plasmonics 6(3):435?444 (2011);Abraham Ekeroth and Lester, Plasmonics 7(4):579?587, (2012);Abraham Ekeroth and Lester, Plasmonics 8:1417?1428 (2013)), weperformed an exhaustive study about optical properties of metallicrealistic nanotubes, hollow or with dielectric cores. Based onrigorous calculations, involving experimental-interpolated dielectricfunctions, we pointed out the importance of using an adequatesize-corrected dielectric function in homogeneous bidimensionalmetallic shells when their thicknesses are about severalnanometers. In this paper, we compute optical forces induced byelectromagnetic plane waves on these kind of nanostructures. Wefocus the study under p polarisation, in order to observe plasmonic-related behaviour. The optical forces are calculated by theMaxwell?s stress tensor without any kind of approximation. We showthree examples of mechanical effects on silver thin shells. Thecharacteristics of the electromagnetic interaction in these structures,from the point of view of forces, allow us to comprehend theproblem of the plasmonic interaction in the shell in a new way. Weshow numerically, for the first time, the nature ofbonding/antibonding of surface plasmons in nanotubes made ofrealistic materials, in a way independent of approximations relatedto scale. The behaviour of the realistic silver shells is comparedwith the features deduced from the plasmon hybridization model,which are predicted from a quasi-static approximation ofelectromagnetic response. Our results conceive a full retardedproblem and can only contain numerical errors. In addition, wecompare rigorous calculations for the optical forces with those onesobtained from the far field approach, when specified for shellgeometry.