Near- and Far-Field Optical Response of Eccentric Nanoshells

Abstract

We study the optical response of eccentric nanoshells (i.e., spherical nanoparticles with an eccentric spherical inclusion) in the near and the far field through finite-difference time-domain simulations. Plasmon hybridization theory is used to explain the obtained results. The eccentricity generates a far-field optical spectrum with various plasmon peaks. The number, position, and width of the peaks depend on the core offset. Near-field enhancements in the surroundings of these structures are significantly larger than those obtained for equivalent concentric nanoshells and, more importantly, they are almost independent of the illumination conditions. This opens up the door for using eccentric nanoshells in applications requiring intense near-field enhancements.

Enhanced control of plasmonic properties of silver–gold hollow nanoparticles via a reduction-assisted galvanic replacement approach

“…2B-F) LSPR spectra, which are not affected by heterogeneous broadening (Table S2 †). These single-particle LSPR spectra indeed display a large distribution arising from particle-toparticle variations in, primarily, diameter and wall thickness, but also in void concentricity, 16,19,42 surface roughness and the presence of pinholes, 43,44 all of which alter optical properties. Interestingly, although composition may play a role in the observed scattering intensity it is not the dominant effect (Fig.…”

Applications of Hybrid Metal‐Dielectric Nanostructures: State of the Art

“…Also, the possibility of manufacturing them in a controlled manner makes these nanounits very attractive for many application purposes where good tunable plasmonic performances are necessary. [213,214,237,238] In ref. [237], the near-and far-field, optical properties of core-shell NPs with reduced symmetry were analyzed.…”

“…The different spectral response of these geometries (in the quasi-static limit) can be understood by means of a plasmon hybridization model. [214,238,239] The electromagnetic behavior of eccentric NPs depends on their geometry, orientation with respect to the impinging radiation, and variations in the dielectric environment. [240] In, [213] the ability of Au nanocups to redirect the scattered light in a direction dependent on the cup orientation was demonstrated.…”

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