对称双缺陷光子晶体的可调谐滤波特性分析*

摘要

基于光子晶体的光子局域特性，并利用光子晶体的介观压光效应，提出了一种新型的双通道可调滤波器结构。采用传输矩阵法对该滤波器的光学传输特性进行了理论推导，建立了透射谱与光子晶体结构参数的关系，讨论了介观压光效应对双缺陷光子晶体透射谱的影响，并对所设计的光子晶体结构进行了数值模拟。结果表明：随着入射角度的增大，缺陷峰发生蓝移。随着各介质层折射率或几何厚度的增加，缺陷峰发生红移。当光子晶体发生轴向拉伸应变时，缺陷峰的位置向长波长移动，但缺陷峰的峰值大体不变，从而验证了此滤波器的可调节性。该光子晶体滤波器结构紧凑，可调谐性好，为光子晶体激光器及传感器的设计提供了一定的理论参考。%A dual channel tunable filter structure has been proposed based on the local characteristic of photonic crystals and the mesoscopic calender effect of photonic crystals. The optical transmission characteristics of the filter have been derived theoretically using the transfer matrix method, and the relationship between the transmission spectrum and structural parameters of photonic crystals has been established. Problems how the mesoscopic calender effect influences the transmission spectrum of photonic crystals with dual defects have been discussed and the structure of photonic crystals has been numerically simulated. The emulational results show that defect modes have a blue shift with the increase of the incident angle, while they have a red shift with the increase of dielectric layers’ refractive index or geometrical thickness. When in photonic crystals occurs axial stretched strain, the locations of defect modes will move towards long wavelength side, but the values of defect peaks keep constant generally. Thereby, the filter’s tunable property has been verified. This photonic crystal filter with good tunability has a compact structure, which may provide a certain theoretical reference for the design of photonic crystal lasers and sensors.