新型金属-多层绝缘介质-金属表面等离子波导结构的传输特性

Transmission Property of Metal-multi-insulator-metal Waveguide

设计了一种新型金属-多层绝缘介质-金属表面等离子波导结构,利用时域有限差分法对其传输特性进行数值分析。研究了有效折射率和传播长度与中间多层绝缘介质厚度之间的关系,并分析了金属层的角度对该波导结构中场分布的影响。结果表明:当光波从波导结构上方垂直入射时,电磁场被限制在多层介质中的高折射率区,实现了场的耦合传输。多层绝缘介质的厚度均为220 nm时,正六边形金属层结构对应的波导结构的传输性能较为理想。该结构能够实现亚波长尺度的光限制,可以应用于光电子集成和传感器领域。

A metal-multi-insulator-metal surface plasmon waveguide was proposed,and finite-difference time-domain method was employed to research the transmission property. The dependence of thickness of insulators on effective refractive index and propagation length were investigated. The effect of angle of metal layer on the field distribution in waveguide was also analyzed. The simulation results show that the electromagnetic field is confined in high index region and coupling transmission is realized as the light wave is normally incident. The transmission characteristic of waveguide with regular hexa-gon metal is relative well as the thickness of multi-insulator is 220 nm. This waveguide is able to complete the light confinement at subwavelength scale and applied in electronics integration and sensor.