Study of one-dimensional defect photonic crystal based on Ag-anodic aluminum oxide composites with super low refractive index

Abstract

The super low refractive index was obtained through depositing metal Ag into an anodic aluminum oxide (AAO) template to form a Ag-AAO composite, and was introduced into a one-dimensional photonic crystal (1D PC) to form defect structures. Then their optical responses were simulated by using the finite difference time domain (FDTD) method, and comparison was made with optical responses of the conventional 1D TiO₂/SiO₂ dielectric defect PC. It is found that for the all studied 1D defect PCs, the red shift of the defect peak is nearly linear with the increase of the thickness of the defect layer, and the quality factor Q of the defect peak lying in the center of photonic band gap has the highest value. Furthermore, among the studied 1D defect PCs, the fundamental structure 1D TiO₂/Ag-AAO PC forming the 1D cavity defect PC structure can clearly weaken the dependence of the defect state position on the incident angle; the introduction of Ag-AAO defect layer and incident angle can enhance the quality factor Q of the defect peak, and the 1D TiO₂/Ag-AAO PC cavity with TiO₂ defect layer has the highest-quality factor.