Research On Characteristics Of The Optical Waveguides With Double Negative Materials

In1968, Veselago predicted originality that a material of which both the permittivity and permeability are simultaneously negative also comes into Maxwell Equations. A medium of this type possesses some peculiar electrodynamics properties, such as negative index of refraction, inverse Doppler effects, reversed Cerenkov radiation. Depending on the Pendry theoretical model, artificial DNG material was obtained for the first time by Smith. Since the existence of DNG was demonstrated, much attention has been received recently on the study of DNG. With increasing fabricating techniques, the frequency range of DNG material continues to spread In2006, M. S. Wheeler made DNG material working in infrared band successfully. From then on, properties of optical waves propagating in DNG waveguide attract much more attention. In this paper, we use Maxwell equations to analyze the three-layers and five-layers slab waveguides including DNG materials. Our original jobs in research are listed as follow:1) Two different optical slab waveguides with double-negative (DNG) material were discussed in detail. The dispersion relations of an asymmetric DNG slab waveguide were investigated by using normalized parameters. A number of unusual properties were proposed. For instance, when the slab waveguide was composed by DNG substrate, for guided modes, fundamental mode exists all the way, but only in a small low frequency range. TE1modes act as other high modes, double degeneracy exists near cut frequency. The existence and the type of the surface mode solutions with respect to different parameters are classified systematically and discussed in detail. TEo mode exists only in one case. When the slab waveguide is composed by DNG cover layer. TEo guided mode can exists when parameters are suitable. Fist order mode behaves as other higher order modes and exists up to infinite high frequency. Higher order modes have no double degeneracy. For the two models, TE1surface mode exists only in one case, and the dispersion curve of TE1surface mode continues with that of oscillating TEo mode, it seems that the two different kinds of modes compensate each other to form one whole mode. TM modes were involved too.2) Five layers slab waveguide filled with DNG material was studied in this paper, dispersion equation, propagation power, normalized z energy flow and the effective guide thickness expressions which are very important describing slab waveguide were obtained. The dispersion curves, effective thickness and normalized energy propagation curves are given in this paper. Both TE and TM modes were discussed.