介质覆盖金属光栅混合表面等离子模式光学特性研究

摘要

采用时域有限差分法与耦合模理论,研究了介质覆盖金属光栅表面等离子混合模式的光学共振特性.研究结果表明,在所研究的结构中,覆盖介质支撑的混合表面模式与金属光栅所支撑的表面等离子模式相互作用引起抗交叉效应;利用耦合模理论,对此系统的反射特性进行了建模研究,得出了减小吸收的条件.此耦合系统的所有光学特性都采用了时域有限差分法进行验证,理论结果与数值模拟结果一致.%The optical properties of resonant guided modes in a system with metallic grating covered by dielectric mate-rial are investigated by the finite-difference time-domain method and coupled-mode theory. Two kinds of guided reso-nant modes, the hybrid surface modes supported by the dielectric material and plasmonic surface modes supported by the metallic grating,are mutually coupling and mixing due to anti-crossing. The optical reflective properties of the sys-tem are also modeled and investigated by the coupled-mode theory. Conditions for the absorption reduction are also ob-tained. All the characteristics of the coupling systems are confirmed numerically by the finite-difference time-domain method.