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Published August 2009 | public
Journal Article

Plasmon Dispersion in Coaxial Waveguides from Single-Cavity Optical Transmission Measurements


We determine the plasmon dispersion relation in coaxial waveguides composed of a circular channel separating a metallic core and cladding. Optical transmission measurements are performed on isolated coaxial nanoapertures fabricated on a Ag film using focused ion-beam lithography. The dispersion depends strongly on the dielectric material and layer thickness. Our experimental results agree well with an analytical model for plasmon dispersion in coaxial waveguides. We observe large phase shifts at reflection from the end facets of the coaxial cavity, which strongly affect the waveguide resonances and can be tuned by changing the coax geometry, composition, and surrounding dielectric index, enabling coaxial cavities with ultrasmall mode volumes.

Additional Information

© 2009 American Chemical Society. Received February 24, 2009; Revised Manuscript Received July 8, 2009. Publication Date (Web): July 15, 2009. The authors gratefully acknowledge helpful discussions with J. A. Dionne, A. F. Koenderink, H. J. Lezec, and E. Verhagen. We acknowledge financial support from the National Science Foundation, under Grant DMR 0606472; portions of this work were performed in facilities sponsored by the Center for Science and Engineering of Materials, an NSF MRSEC. This work is also part of the research program of the "Stichting voor Fundamenteel Onderzoek der Materie (FOM)", which is financially supported by the "Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)". It was also supported by "NanoNed", a nanotechnology program funded by the Dutch Ministry of Economic Affairs.

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October 18, 2023