Tsai, M.-W.M.-W.TsaiChuang, T.-H.T.-H.ChuangChang, H.-Y.H.-Y.ChangSI-CHEN LEE2020-06-112020-06-11200600036951https://scholars.lib.ntu.edu.tw/handle/123456789/498766https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748256661&doi=10.1063%2f1.2338886&partnerID=40&md5=40b19b4b9fa5f008ed26f5f15b1e4411Extraordinary optical transmission through a two-dimensional Ag film in the far infrared region was demonstrated. The holes were rectangular and arranged in a square lattice. When either the width or the length size of the rectangular holes was close to the half of the lattice constant a/2, the degenerate (±1,0) Ag/Si or (0,±1) Ag/Si modes split into two peaks. Additionally, the surface plasmon dispersion relations of the square hole array with different aspect ratios of holes were measured. As the aspect ratio increased, the surface plasmon tended to couple strongly with the local charge dipole oscillations in a direction perpendicular to the long edges. The charge dipole oscillation parallel to the long edges gradually disappeared. This is confirmed by experiments using the polarized light. The dynamic properties of the surface plasmon dispersion relations show the interaction among localized surface plasmons and its mechanism. © 2005 American Institute of Physics.Aspect ratio; Crystal lattices; Infrared radiation; Oscillations; Silver; Surface plasmon resonance; Hole arrays; Square lattices; Surface plasmon dispersion; Surface plasmon polaritons; Optical filmsjournal article10.1063/1.23388862-s2.0-33748256661