Posted August 26, 2016 by fismots in Research Results

Photonic states mixing beyond the plasmon hybridization model

Mixing-sceme
Mixing-sceme

A study is performed on a photonic-state mixing-pattern in an insulator-metal-insulator cylindrical
silver nanoshell and its rich variations induced by changes in the geometry and dielectric media of
the system, representing the combined influences of plasmon coupling strength and cavity effects.
This study is performed in terms of the photonic local density of states (LDOS) calculated using
the Green tensor method, in order to elucidate those combined effects. The energy profiles of
LDOS inside the dielectric core are shown to exhibit consistently growing number of redshifted
photonic states due to an enhanced plasmon coupling induced state mixing arising from decreased
shell thickness, increased cavity size effect, and larger symmetry breaking effect induced by
increased permittivity difference between the core and the background media. Further, an increase
in cavity size leads to increased additional peaks that spread out toward the lower energy regime. A
systematic analysis of those variations for a silver nanoshell with a fixed inner radius in vacuum
background reveals a certain pattern of those growing number of redshifted states with an analytic
expression for the corresponding energy downshifts, signifying a photonic state mixing scheme
beyond the commonly adopted plasmon hybridization scheme. Finally, a remarkable correlation is
demonstrated between the LDOS energy profiles outside the shell and the corresponding scattering
efficiencies.

Principal researcher: Alexander A. Iskandar
Funding: Penelitian Unggulan Perguruan Tinggi, Indonesian Ministry of Education and Culture (Contract No. 310q/I1.C01/PL/2015)

JOURNAL OF APPLIED PHYSICS 120, 043105 (2016)
http://dx.doi.org/10.1063/1.4959258