Coupling between localized resonance and excitation of surface waves in metal hole arrays

We investigate the transition of the dominant resonant transmission mechanism from localized resonance to excitation of surface waves and vice versa in metal hole arrays. The transition occurs continuously with a change in the length of the rectangular holes. We also study the effect of the incident-beam diameter and surface condition on the transmission spectrum. Our experimental results show the important differences between the two mechanisms. They also confirm the theoretical prediction of Bravo-Abad [Phys. Rev. B 76, 241102(R) (2007)].ArticlePHYSICAL REVIEW B. 79(15):153405 (2009)journal articl

Far -Infrared Study of Two-Dimensional Air-Rod Photonic Crystals : Band Gap, Uncoupled Mode and Wavevector Mismatch

Two-dimensional photonic crystals both of square and triangular lattices composed of circular air-rods with the lattice constant of 170 μm were fabricated. The photonic band structures were studied by far-infrared transmission measurements. The clear opaque regions due to the band gap and due to the non coupling between photonic mode and external wave were observed in both lattices. The uncoupled modes can not be excited by an external mode because their wave functions are anti-symmetric under the relevant mirror reflection defined on the lattice. Furthermore, some regions with very low transmittance were found, where exist only a band whose dominant plane-wave component in eigen-function has wavevector not parallel to the propagating direction of the external incident wave. These low transmittance are considered to be caused by wavevector mismatch between photonic modes and external incident waves. The observed spectra are discussed compared with the results of band structure calculated by means of a plane-wave expansion method as well as of the symmetry consideration.Article信州大学理学部紀要 31(2): 89-104(1997)departmental bulletin pape

Effect of dielectric thin films on reflection properties of metal hole arrays

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 96(2):021106 (2010) and may be found at https://doi.org/10.1063/1.3292024 .We study the effect of a dielectric film attached to the surface of a metal hole array (MHA) on the reflection spectrum in the terahertz (THz) region. The frequency of the reflection dip, attributed to the excitation of surface waves in the vicinity of the MHA surface, shifts to lower frequencies with increasing dielectric film thickness. This resonant characteristic of MHAs can be applied to highly sensitive THz sensing for samples attached to the MHA surface. We also investigate the dependence of the reflection spectrum on the MHA's thickness and the side to which the dielectric film is attached.ArticleAPPLIED PHYSICS LETTERS. 96(2):021106 (2010)journal articl

Effect of dielectric thin films on reflection properties of metal hole arrays

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 96(2):021106 (2010) and may be found at https://doi.org/10.1063/1.3292024 .We study the effect of a dielectric film attached to the surface of a metal hole array (MHA) on the reflection spectrum in the terahertz (THz) region. The frequency of the reflection dip, attributed to the excitation of surface waves in the vicinity of the MHA surface, shifts to lower frequencies with increasing dielectric film thickness. This resonant characteristic of MHAs can be applied to highly sensitive THz sensing for samples attached to the MHA surface. We also investigate the dependence of the reflection spectrum on the MHA's thickness and the side to which the dielectric film is attached.ArticleAPPLIED PHYSICS LETTERS. 96(2):021106 (2010)journal articl

Characteristics and generation process of surface waves excited on a perfect conductor surface

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: https://doi.org/10.1364/OE.18.017576 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.We investigate characteristics and generation process of surface waves excited on a structured perfect conductor surface in order to clarify the mechanism of resonant transmission in metal hole arrays made of the perfect conductor. By using a metal hole array of kagome lattice, we can separate two modes excited on the perfect conductor surface; a surface wave and an edge mode. Our calculation based on finite-difference time-domain method provides a generation process of the edge mode and the surface wave that is responsible for the resonant transmission in metal hole arrays. (C) 2010 Optical Society of AmericaArticleOPTICS EXPRESS. 18(16):17576-17583 (2010)journal articl

Three-dimensional bulk metamaterials operating in the terahertz range

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 96(8):081105 (2010) and may be found at https://doi.org/10.1063/1.3327830 .Three-dimensional bulk metamaterials that operate in the terahertz (THz) frequency range were fabricated by stacking 100 two-dimensional sheets containing metallic split-ring resonators (SRR) on thin polyethylene terephthalate film substrates. The THz magnetic resonance for the incident magnetic field perpendicular to the plane of the SRR structure was measured. We also investigated the dependence of the magnetic resonant strength on the metal thickness.ArticleAPPLIED PHYSICS LETTERS. 96(8):081105 (2010)journal articl