Controllable characteristics of interface states in one-dimensional inverted symmetric photonic structures

Abstract

Using the transfer matrix method, the tunable characteristics of the interface state generated by one-dimensional photonic structure with inversion symmetry are studied, and the samples are prepared by electron beam evaporation technology for experimental verification. According to the different inversion symmetry centers of unit cell, the inverted symmetric layered photonic structures are divided into two types i.e. PCI and PCII. The calculation results show that for the combined structure composed of PCI and PCII, there is an interface state at a characteristic frequency where the sum of the imaginary parts of the surface impedance of PCI and PCII is equal to zero, and this frequency of the interface state is independent of the number of unit cells. On this basis, if a PCI structure is added to form PCI + PCII + PCI photonic structure, two interface states will be generated in the same band gap, and changing the unit cell number in each or part of of individual PCI and PCII structures, the frequencies of two interface states can be regulated. The experimental results show that the regulation of interface state by controlling unit cell number is feasible, which provides a more flexible idea for designing the extremely narrow-band filters and multi-channel filters to meet different application requirements.