Subwavelength-confined hybrid surface modes of low attenuation in cylindrical metallic-dielectric waveguides

¹ State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University - Beijing 100871, China
² State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University Hangzhou 310027, China

^a ygu@pku.edu.cn
^b qhgong@pku.edu.cn

Received: 18 March 2011
Accepted: 6 September 2011

Abstract

Subwavelength-confined hybrid surface modes of low attenuation were found in a cylindrical waveguide with a high-permittivity-dielectric nanocore nested in a metallic nanotube. When phase-matching conditions are met, mode transfer occurs, which is associated with a strong anti-crossing behavior. At the transfer radius, a hybrid mode with superior properties, namely low propagation attenuation and high light confinement, transforms into the other that has inferior properties. Thus, the superior mode with subwavelength confinement can be efficiently excited through this mode-transfer process when we taper the nested nanocore. This nanoscale cylindrical metallic-dielectric waveguide may have applications in high-density integrated photonic circuits, plasmonic sources, and biosensing techniques.