Evolution of Plasmonic Modes in a Metal Nano-Wire Studied by a Modified Finite Element Method

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/JLT.2017.2782710, Journal of Lightwave Technology  Abstract-A finite width thin metal film plasmonic nanowire with its unique feature of sub-wavelength light guiding is finding many applications in compact integrated nanophotonic circuits and sensors. Full-vectorial finite element method (FV-FEM) is becoming an important simulation tool for the analyses of such exotic waveguides. Instead of a penalty approach reported earlier, a more direct divergence formulation considering each discretized element's optical properties to eliminate non-physical modal eigenvectors has been exploited and is reported here. Long and short-range fundamental and higher order plasmonic modes and supermodes of a pure metal nanowire and their evolutions with waveguide geometry, surrounding identical and non-identical dielectric cladding materials and operating wavelength are thoroughly studied. Interesting long-range modal properties such as, supermode formation, complex phase matching and mode evolution in identical and non-identical clad metal nanowires have been observed and explained in detail including supermode profiles. This study is expected to help in understanding the evolution of plasmonic guided modes in compact active and passive integrated photonic devices containing metal narrow strips. Permanent repository link

Design of on-chip hybrid plasmonic Mach-Zehnder interferometer for temperature and concentration detection of chemical solution

“…In most cases, the PDEs for plasmonic problems are much complex to be solved by using conventional analytical and semianalytical approaches. Our in-house H-field based full-vectorial finite element method (FV-FEM) has been developed [45] and refined [34,44,46,47] over last thirty years is used for modal solutions. The variational formulation used for FV-FEM is modified by considering local dielectric constant of each discretized element for the elimination of spurious modes, particularly useful for plasmonic waveguides [44,47] so that their Euler equations not only follow the Helmholtz's equation but also satisfy the Maxwell's divergence equation.…”

Enhancing Propagation Length of Surface Plasmon Polaritons by Using Metallic Double-Layer Structure

“…The mode confinement fundamentally depends on the geometrical structure of the plasmonic waveguide and metal used for forming the metal/dielectric interface. To date, various types of plasmonic waveguides have been proposed for improving the propagation length while keeping the propagation mode area at a subwavelength size such as metallic nanowires [19], metal strips [20], and wedge-shaped waveguides Fig. 1.…”

Wedge Surface Plasmon Polariton Waveguides Based on Wet-Bulk Micromachining

“…The possibility of an electromagnetic energy concentration and low loss propagation fundamentally depends on the geometrical structure of the SPP waveguide. Typical SPP waveguide structures are reported in the literature, such as metallic nanowires [2,3], metal strips [4,5], an array of metal nanoparticles [6], V-shaped waveguides [7,8] and wedge-shaped waveguides [9][10][11]. The structure of an SPP waveguide usually consists of a thin metallic layer deposited directly on a dielectric or separated from a dielectric by an insulator.…”