Generalized local analogue model for nonlocal plasmonic nanostructures based on multiple-fluid hydrodynamic framework

Abstract

Spatial dispersion plays a critical role in nanophotonics when small plasmonic structures with feature sizes of few nanometers are handled. Such nonlocality is typically considered in a hydrodynamic framework and generally requires solving coupled partial differential equations, and therefore is involved. We develop a generalized local analogue model to reflect the nonlocal effects of plasmonic structures and avoid the complicated analysis within the multiple-fluid hydrodynamic framework, where more than one kind of charge carriers is considered. We show that spatial nonlocality can be represented by simply replacing the nonlocal surface region with an in-situ artificial local dispersive film. With such an elegant and simple-to-use alternative, the conventional analysis and simulations in the local regime acquire nonlocal capability, sufficient for a quantitative description of various plasmonic structures in nanoscale, rendering a much simpler process and great practical advantages in the numerical treatment.

Nonlocal Soft Plasmonics in Planar Homogeneous Multilayers

“…Such a two-fluid model was furthermore used to investigate nonlocal interactions in electron-hole pairs of semiconductors [45,46]. A generalized multi-fluid model has recently been developed [47].…”

Impact of Nonlocality on Group Delay and Reflective Behavior Near Surface Plasmon Resonances in Otto Structure

“…Simultaneously, it has been applied to transformation-optics approaches to investigate the optical response of non-trivial plasmonic metasurfaces [ 26 , 27 ]. Up to now, research on the spatial dispersion based on the hydrodynamical mode has concentrated on two directions: (i) developing numerical tools based on the hydrodynamical mode to take account for the phenomena in different structures [ 15 , 23 , 28 , 29 ] and (ii) theoretically studying the effect of the spatial dispersion [ 24 , 30 , 31 ].…”

Nonlocal Optical Response of Particle Plasmons in Single Gold Nanorods

“…The GNOR theory has successfully explained both size-dependent plasmon line width broadening and resonance energy blue shifts in single metallic nanoparticles . To facilitate its implementation in any electromagnetic simulation platform, we have extended it to the generalized nonlocal optical response theory-based local analogue model (GNOR-LAM) by combining the local analogue model (LAM) with GNOR theory. , This approach eliminates the need for implementing a k -dependent permittivity and simplifies the simulation of plasmonic nanoparticles of different shapes. The optical response of metals in the frequency domain can be described by employing the coupled electromagnetic equations with GNOR theory: ∇ × ∇ × E false( boldr , ω false) = ( ω / c ) 2 ε core false( ω false) E false( boldr , ω false) + i ω μ 0 J false( boldr , ω false) false[ β 2 / ω ( ω + i γ ) + scriptD / i ω false] ∇ false[ ∇ · boldJ ( r , ω ) false] + J false( boldr , ω false) = σ false( ω false) J false( boldr , ω false) where induced current density J ( r , ω) represents the movement of free electrons in response to the incident electromagnetic field while the dielectric response from the bound electrons is denoted by ε core ( ω ).…”

“…12 To facilitate its implementation in any electromagnetic simulation platform, we have extended it to the generalized nonlocal optical response theorybased local analogue model (GNOR-LAM) by combining the local analogue model (LAM) with GNOR theory. 21,22 This approach eliminates the need for implementing a k-dependent permittivity and simplifies the simulation of plasmonic nano-particles of different shapes. The optical response of metals in the frequency domain can be described by employing the coupled electromagnetic equations with GNOR theory: 23 c i…”

“…By exploiting the tunable scattering spectra of gold nanorods via their aspect ratio, we investigate the nonlocal optical response of gold nanorods in the near-infrared region where interband damping is absent. To examine the role of the induced charge diffusion constant ( ) and electron convection constant ( β ) in determining the nonlocal optical response of single gold nanorods, we compare the experimentally obtained spectral characteristics with the values simulated by the boundary element method (BEM) using a generalized nonlocal optical response theory-based local analogue model (GNOR-LAM). ,− Our results reveal that the value of in the nonlocal optical response of single gold nanorods is smaller than the previously reported value in the context of plasmon-coupled systems. Our method offers a promising approach to understanding nonlocal optical responses on the single-nanoparticle level.…”