研究分析了金属-介质-金属(MIM)波导布拉格光栅(WBG)结构中的反对称和对称等离激元模式的色散关系和传输特性。计算分析了金属为银、介质层厚度为700 nm时,不同介质材料情况下两种模式的截止特性及色散关系。在此基础上用布洛赫模式分析法探讨了两种介质交替排列构成的MIM WBG结构的反对称与对称模式的能带结构;并用传输矩阵法计算了透射谱,发现结构在通信波段的模式滤波特性。进一步讨论了对称模式的截止频率、模式传输特性与材料和结构参数的依赖关系。通过对结构材料参数及几何尺寸的选择及优化,可以实现在特定波段的宽带或窄带滤波及模式滤波功能,该结构在光通信、集成光学领域具有一定的应用价值。

The dispersion and transmission characteristics of antisymmetric bound and symmetric bound modes in metal-insulator-metal (MIM) waveguide Bragg grating (WBG) structure are analyzed. The cut-off property and dispersion relations of the two modes with different dielectric materials are discussed, when the metal is set as silver and the insulator thickness is 700 nm. On the basis of this, the band structure of the antisymmetric and symmetric modes of the MIM WBG structure is proposed by using the Bloch mode analysis method. The transmission spectrum is calculated by transfer matrix method, and mode filtering properties of the structure in communication waveband are found. Furthermore, the dependent relationship between the cutoff frequency of the symmetrical mode, the mode transmission characteristic, the material and structural parameters is discussed. Through the selection and optimization of material parameters and geometrical dimensions, mode filter function can be achieved in a particular band, which can be broad or narrow. The structure has potential applications in the field of optical communications and integrated optics.