Estimation of Surface Waves along a Metal Grating Using an Equivalent Impedance Model

Michinari SHIMODA  Toyonori MATSUDA  Kazunori MATSUO  Yoshitada IYAMA  

IEICE TRANSACTIONS on Electronics   Vol.E95-C    No.4    pp.717-724
Publication Date: 2012/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E95.C.717
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electromagnetic Theory
electromagnetic waves,  diffraction grating,  surface wave,  plasmon-resonance absorption,  

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The cause-and-effect relation between plasmon-resonance absorption and surface wave in a sinusoidal metal grating is investigated. By introducing an equivalent impedance model, similar to an equivalent circuit on an electric circuit, which is an impedance boundary value problem on the fictitious surface over the grating, we estimate the surface wave from the eigen field of the model by using the resonance property of the scattered field. Through numerical examples, we illustrate that the absorption in the grating occurs in the condition of exciting the surface wave along the model, and the real part of the surface impedance is negative on about half part of the fictitious surface in the condition.