光子晶体纳米梁侧耦合孔径啁啾光子晶体纳米梁腔结构的Fano共振传感机理

Fano Resonance-Sensing Mechanism of Photonic Crystal Nanobeam Side-CouplingAperture Chirped Photonic Crystal Nanobeam CavityStructure

基于Fano共振原理,提出光子晶体纳米梁侧耦合孔径啁啾光子晶体纳米梁腔结构。由光子晶体纳米梁所产生的宽的连续态与由光子晶体纳米梁腔所产生的窄的离散态干涉相消实现Fano共振。基于耦合模理论,定性分析该结构中Fano共振的产生机制,利用时域有限差分法对该结构进行模拟仿真,定量分析结构参数对折射率传感特性的影响,并对结构参数进行优化分析。结果表明,优化后的结构品质因子值可高达5.1×10^3,这将为集成光子晶体波导传感器件设计提供有效的理论参考和技术指导。

This study proposes a photonic crystal nanobeam(PCN)side-coupling aperture chirped photonic crystal nanobeam cavity(PCNC)structure based on the Fano resonance principle.The Fano resonance can be realized by the destructive interference between the wide continuous state produced by the PCN structure and narrow discrete state generated by the PCNC structure.The generation mechanism of Fano resonance in the structure is qualitatively analyzed via the coupled mode theory,and the structure is simulated by using the finite-difference time-domain method.After quantitatively studying the influences of the structural parameters on the refractive-index sensing characteristics of the system,the structural parameters are optimized.Results show that the optimized figure of merit is as high as 5.1×10^3,providing an effective theoretical reference and technical guidance for the design of integrated photonic-crystal waveguide sensors.