Robust multispectral transparency in continuous metal film structures via multiple near-field plasmon coupling by a finite-difference time-domain method

Abstract

We propose a robust multispectral transparent plasmonic structure and calculate its transparency response by using the three-dimensional finite-difference time-domain (FDTD) method. The proposed structure is composed of a continuous ultrathin metal film sandwiched by double two-dimensional (2D) hexagonal non-close-packed metal-dielectric multilayer core-shell nanoparticle arrays. The top and bottom plasmonic arrays in such a structure, respectively, act as the light input and output couplers to carry out the efficient trapping and release of light. Near-perfect multispectral optical transparency in the visible and near-infrared regions is achieved theoretically. The calculated electric field distribution patterns show that the near-perfect multispectral optical transparency mainly originates from the excitation and hybridization of shell and core plasmon modes, strong near-field coupling of dipole plasmon modes between adjacent nanoparticles as well as the excitation of surface plasmon waves of the metal film. The robust transparency bands can be efficiently tuned in a large range by varying the structural parameters and the surrounding dielectric environment. The proposed structure also shows additional merits such as a deep sub-wavelength size and fully retained electrical and mechanical properties of the natural metal. These features might provide promising applications in highly integrated optoelectronic devices including plasmonic filters, nanoscale multiplexers, and non-linear optics.

Continuous copper film structures with broadband optical transparency

“…The closely packed PA and the OC coated on a metal film's surfaces act as the efficient light couplers. In comparison with the previous reports [10][11][12], the PA and the common OC used here can simplify the fabrication process. Particularly, for a spherical core-shell PA, the fabrication could be further simplified via using the colloidal self-assembly methods [13][14][15].…”

Improving Plasmon Sensing Performance by Exploiting the Spatially Confined Field

“…Although there only partial confined optical field is exploited for the sensing due to the thick supporting layer used for the suspended plasmonic disks array, noticeable improvement for the sensing detection is still achieved. Three-dimensional finite-difference time-domain method is employed to calculate the optical properties [31,32]. Periodic boundary conditions are used in the xoy plane to reproduce the periodic crystal.…”

Dielectric shell modulated plasmonic crystal for novel light absorption meta-surface

“…The Au reflector is with a 100-nm-thick to completely inhibit the light transmission through the structure. Three-dimensional finite-difference time-domain method has been employed to theoretically measure the optical properties and behaviors of the field [25]. Dielectric permittivity of Au is described by the well-known Drude model with those experimental data reported by Johnson and Christy [25]: ε(ω) = 1 − ε p 2 / (ω + iω c ω) with the plasma frequency ε p = 2π × 2.175 × 10 15 s −1 and the damping constant ω c = 2π × 6.5 × 10 12 s −1 .…”