Optimization of field propagation in optical coaxial nano-waveguides of complicated-form

Abstract

The properties of new optical waveguides with nanosize cross-section made of noble metals and glasses are described. As was found, this waveguide supports propagation of modes with unusual propagation properties. For estimation of the field localization, losses, propagation length, velocity and others characteristics the numerical simulations by FEM method has been used. The set of advanced structures are studied: a conventional coaxial; a coaxial waveguide with periodically arrange metal tubes for reducing the metal part in the structure; the coaxial waveguides with elliptic-type central rod and two cross ellipses. The effects of the asymmetry of the central part those structures have been estimated. The comparison of the results of this investigation by wavelength deviation has been performed. A combination of noble metal plus active glasses has been estimated towards minimization of losses. The power flow distribution for different types of modes is investigated. The best characteristics can be achieved for the dipole-like modes which can be excited by an external dipole.