包含左手材料的四层平板波导中的光导模

Guided Modes in a Four-layer Slab Waveguide with the LHM Core

研究一个芯子层是左手材料,其他三层由传统材料构成的四层平板光波导系统,利用图解法对各种TE偏振的导波模式的解进行详细分析。研究表明,四层左手材料光波导既能支持振荡导模,也能支持表面导模,与三层左手材料光波导相比较,此四层波导的导波模式呈现一些新的特性。对于中间传统材料层存在振荡场的情形:芯子层支持振荡导模的光波导中存在基模,并且高阶振荡导模出现模式缺失的性质;芯子层支持表面导模的光波导可以支持基模和多个高阶模式,并且存在模式兼并的性质。对于中间传统材料层存在衰减场的情形,此四层波导结构可等效为三层左手材料光波导。这些新的光波导传输性质对各种光波导器件的制作有潜在的应用价值。

The guided modes are studied in a four-layer left-hand meterial （LHM） slab waveguide structure with a negative refractive material core and three traditional dielectric layer. The graphical method is applied to determine the TE guided modes. The LHM waveguide supports both oscillating guided modes and surface guided modes. The guided modes in the four layer LHM waveguide have some new properties compared to the three-layer waveguide. When the oscillating field exists both in the inner traditional dielectric layer and in the LHM layer,the fundamental mode appears and some high-order modes are absent. And when surface guided modes exist in the LHM layer with the oscillating field in the inner dielectric layer,mode double-degeneracy appears for the high-order modes. The four-layer LHM waveguide is equivalent to the asymmetric three-layer waveguide when the evanescent field exists in the inner dielectric layer. These novel properties are valuable for the fabrication of the optical waveguides in the future.