3 research outputs found
Refractive-index sensing with ultra-thin plasmonic nanotubes
We study the refractive-index sensing properties of plasmonic nanotubes with
a dielectric core and ultra-thin metal shell. The few-nm thin metal shell is
described by both the usual Drude model and the nonlocal hydrodynamic model to
investigate the effects of nonlocality. We derive an analytical expression for
the extinction cross section and show how sensing of the refractive index of
the surrounding medium and the figure-of-merit are affected by the shape and
size of the nanotubes. Comparison with other localized surface plasmon
resonance sensors reveals that the nanotube exhibits superior sensitivity and
comparable figure-of-merit
Perfect imaging, epsilon-near zero phenomena and waveguiding in the scope of nonlocal effects.
7 pags, 4 figsPlasmons in metals can oscillate on a sub-wavelength length scale and this large-k response constitutes an inherent prerequisite for fascinating effects such as perfect imaging and intriguing wave phenomena associated with the epsilon-near-zero (ENZ) regime. While there is no upper cut-off within the local-response approximation (LRA) of the plasma polarization, nonlocal dynamics suppress response beyond ω/v F, where v F is the Fermi velocity of the electron gas. Nonlocal response has previously been found to pose limitations to field-enhancement phenomena. Accounting for nonlocal hydrodynamic response, we show that perfect imaging is surprisingly only marginally affected by nonlocal properties of a metal slab, even for a deep subwavelength case and an extremely thin film. Similarly, for the ENZ response we find no indications of nonlocal response jeopardizing the basic behaviors anticipated from the LRA. Finally, our study of waveguiding of gap plasmons even shows a positive nonlocal influence on the propagation length. © 2013 Macmillan Publishers Limited. All rights reserved.C. D. acknowledges a FPU fellowship by the Spanish Ministerio de Educación. J. C. gratefully acknowledges financial support from the Danish Council for Independent Research and a Sapere Aude grant (12-134776). The Center for Nanostructured Graphene is sponsored by the Danish National Research Foundation, Project DNRF58