Comparison of numerical methods in near-field computation for metallic nanoparticles

In the quest aimed at unveiling alternative plasmonic elements overcoming noble metals for selected applications in photonics, we investigate by numerical simulations the near ultraviolet-tonear infrared optical response of solid and liquid Bi nanospheres embedded in a dielectric matrix. We also determine the resulting transmission contrast upon reversible solid-liquid phase transition to evaluate their potential for switchable optical filtering. The optical response of the solid (liquid) Bi nanospheres is ruled by localized polaritonic (plasmonic) resonances tunable by controlling the diameter. For a selected diameter between 20 nm and 50 nm, both solid and liquid nanospheres present a dipolar resonance inducing a strong peak extinction in the near ultraviolet, however at different photon energies. This enables a high transmission contrast at selected near ultraviolet photon energies. It is estimated that a two-dimensional assembly of 30 nm solid Bi nanospheres with a surface coverage of 32% will almost totally extinct (transmission of 2%) a near ultraviolet 3.45 eV (359 nm) light beam, whereas upon phase transition the resulting liquid Bi nanospheres will show a transmission of 30%. This work appeals to the fabrication of locally reconfigurable optical metamaterials for integrated switchable near ultraviolet optics.

show abstract

“…Finite element calculations have been performed using the Comsol Multiphysics software. [35][36][37][38][39] The…”

Section: Finite Element Methodsmentioning

confidence: 99%

Polaritonic-to-Plasmonic Transition in Optically Resonant Bismuth Nanospheres for High-Contrast Switchable Ultraviolet Meta-Filters

2016

View full text Add to dashboard Cite

show abstract

“…7. We use as a reference solution the NFM, which has been proved to be accurate in the modeling of ellipsoidal scatterer with moderate eccentricity [29][30][31]50]. We observe in Fig.…”

Section: B Scattering From Oblate and Prolate Spheroidsmentioning

confidence: 99%

“…Elongated or flattened particles can be conveniently simulated in the framework of NFM by using a discrete sources basis [28]. Recently, there was a great effort also to study the near-field properties of metallic nanostructures and complex objects by using the NFM [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Surface integral formulations for the design of plasmonic nanostructures

et al. 2012

View full text Add to dashboard Cite

Numerical formulations based on surface integral equations (SIEs) provide an accurate and efficient framework for the solution of the electromagnetic scattering problem by three-dimensional plasmonic nanostructures in the frequency domain. In this paper, we present a unified description of SIE formulations with both singular and nonsingular kernel and we study their accuracy in solving the scattering problem by metallic nanoparticles with spherical and nonspherical shape. In fact, the accuracy of the numerical solution, especially in the near zone, is of great importance in the analysis and design of plasmonic nanostructures, whose operation critically depends on the manipulation of electromagnetic hot spots. Four formulation types are considered: the N-combined region integral equations, the T-combined region integral equations, the combined field integral equations and the null field integral equations. A detailed comparison between their numerical solutions obtained for several nanoparticle shapes is performed by examining convergence rate and accuracy in both the far and near zone of the scatterer as a function of the number of degrees of freedom. A rigorous analysis of SIE formulations and their limitations can have a high impact on the engineering of numerous nano-scale optical devices such as plasmon-enhanced light emitters, biosensors, photodetectors, and nanoantennas.

show abstract

“…This map shows that the convergence of DDA is much slower near and in the region of the refractive index of silver for optical wavelengths. Karamehmedović et al [21] discovered that DDA produces an unphysically varying internal electric field for silver particles, while Kelly et al [14] presented a similar looking polarization distribution in trigonal silver prisms.…”

Section: Introductionmentioning

confidence: 99%

On the applicability of discrete dipole approximation for plasmonic particles

Vartia

Ylä‐Oijala

Markkanen

et al. 2016

Journal of Quantitative Spectroscopy and Radiative Transfer

View full text Add to dashboard Cite

It has been recognized that the commonly used discrete dipole approximation (DDA) for calculating the optical properties of plasmonic materials may exhibit slow convergence for a certain region of the complex refractive index. In this work we investigate the quantitative accuracy of DDA for particles of different shapes, with silver as the plasmonic material. As expected, the accuracy and convergence of the method as a function of the number of dipoles is relatively good for solid spheres and rounded cubes whose size is of the same order as the wavelength of the localized surface plasmon resonance in silver. However, we find that for solid particles much smaller than the resonance wavelength, and for silver-silica core-shell particles in particular, DDA does not converge to the correct limit even for 10 6 dipoles. We also find that the slow convergence tends to be accompanied by strong, discretization dependent oscillations in the particle's internal electric field. We demonstrate that the main factor behind the slow convergence of the DDA is due to inaccuracies in the plasmonic resonances of the dipoles at the surface of the particles.

show abstract

Comparison of numerical methods in near-field computation for metallic nanoparticles

Cited by 34 publications

References 12 publications

Polaritonic-to-Plasmonic Transition in Optically Resonant Bismuth Nanospheres for High-Contrast Switchable Ultraviolet Meta-Filters

Polaritonic-to-Plasmonic Transition in Optically Resonant Bismuth Nanospheres for High-Contrast Switchable Ultraviolet Meta-Filters

Surface integral formulations for the design of plasmonic nanostructures

On the applicability of discrete dipole approximation for plasmonic particles

Contact Info

Product

Resources

About