基于表面等离子激元理论与金属-介质-金属波导结构提出一个由开口方环共振空腔、挡板及MIM波导组成的波导结构,并使用有限元方法系统地研究了该结构的透射特性.仿真计算结果表明:该结构可以产生法诺共振现象,其共振波长可以通过改变开口方环空腔的长度及开口大小进行调节,该结构敏感度可达1 600nm/RIU,品质因数为1.31×10~5.此外,通过调整方环共振空腔上开口的位置,在波导中产生了双重法诺共振现象,其敏感度可达1 700nm/RIU,品质因数为8.3×10~4.该结构有望在光学集成回路,尤其是纳米生物传感器方面得到比较广泛的应用.
Based on the theory of Surface Plasmon Polaritons (SPPs) and the Metalqnsulator-Metal (MIM) waveguide structure, a waveguide structure was proposed, which consists of a square split-ring resonance cavity, a baffle and a MIM waveguide. The transmission characteristics of this structure is calculated by using the Finlte-Element Method(FEM). The simulation results show a Fano resonance in the transmission spectra, and the resonant wavelength can be easily tuned by changing the length of the square split-ring resonance cavity or the width of the split. The sensitivity and the figure of merit of this structure is 1 600 nm/RIU and 1.3 × 10^5separately. By changing the position of the split, double Fano resonances can be observed in the waveguide with a sensitivity of 1 700 nm/RIU and the figure of merit of 8.3× 10^4 respectively. The waveguide structure may have wide applications in highly integrated optical circuits , especially for nano bio-sensor.