The Simulation And Experimental Study Of One-Dimensional Mirror-Symmetric Photonic Bandgap Structures

The advent of the information age has put forward new requirements for the speed at which people process information.The current development of semiconductor technology restricts the efficiency and rapid processing of information,so using photons to replace electrons has become the key to processing information,because photonic structure can control the motion of photons.Therefore,it is of great significance to study the photonic structure.Due to the unique properties of photonic bandgap and photonic localization,the photonic structure has immediately become a research hotspot in the field of micro-nano photonics since its appearance.With the development of topological photonics in recent years,the impact of structural symmetry on performance arouses people's attention.Among them,the one-dimensional layered structure is easy to realize preparation,having outstanding advantages in practical applications.In this paper,the performance of a one-dimensional layered photonic structure with mirror symmetry and its application in the generation of interface states are calculated and studied,and we can use the electronic beam evaporation technology for experimental preparation and test characterization.The research results can provide a reliable reference for the practical applications of one-dimensional photonic structures in narrow-band filters,multi-channel filters,optical sensors,etc.The main research results are as follows:1.Based on the transfer matrix theory,the photonic structure with one-dimensional mirror symmetry is studied.One-dimensional mirror symmetric structure can be formed by mirroring a layered structure with itself.On the basis of analyzing the spectral characteristics of the structure,the distribution of the imaginary part of the surface impedance of a single photonic structure in different bandgaps is specifically calculated.The results show that the imaginary part of the surface impedance of the structure has different distribution characteristics in different bandgaps.In some band gaps,the sign changes.at the same time,the spectrum of the mirror-symmetric combination structure shows an interface state at the corresponding characteristic frequency.2.The conditions under which one and more interface states are generated in a one-dimensional mirror symmetric photonic structure in the bandgap are analyzed.And study the controllable characteristics of the interface state.The combined photonic structure containing a mirror symmetric plane produces an interface state in the bandgap,and at the characteristic frequency of the interface state,there is a jump in the imaginary part of the surface impedance of a single photonic structure,at the same time the reflection phase of the structure is equal to 0.On this basis,through different combinations,create multiple mirror symmetric planes in the structure,then multiple interface states can be generated in the same bandgap.Further computational research on the characteristics of the interface state,the influence of the number of cells of the photonic structure,the incident angle of the light wave,and the thickness coefficient of the surface of the photonic structure on the interface state are analyzed in detail.Calculations show that as the number of photonic structure cells increases,the bandgap range tends to be stable,and the interface state spectral line width decreases,if the number of structural cells on both sides of the mirror symmetric plane is different,it will lead to a significant decrease in interface state performance;as the incident angle of the light wave increases,the interface state moves to the short wave direction,this shows that in practical applications,the frequency of the interface state can be controlled by changing the incident angle of the light wave.At the same time,the interface state changes regularly with the change of the surface thickness coefficient x.In a structure with a mirror symmetric plane,as x increases from 0,the interface state moves to the short wave direction,when x=0.5,the interface state disappears,as x continues to increase,the interface state moves from the long wave direction to the short wave direction again;in a structure with two mirror symmetric planes,the interval between the two interface states changes with the change of x,but does not overlap.The research results provide a new method for generating one interface state and multiple interface states in the bandgap of one-dimensional mirror symmetric photonic structure,and provide a theoretical reference for the application of one-dimensional mirror symmetric photonic structure to generate interface states.3.Based on electronic beam evaporation technology,the application of one-dimensional mirror symmetry photonic structure to produce interface states is experimentally studied.First by the electronic beam evaporation technology,two kinds of oxide materials,silicon dioxide(Si O₂)and titanium dioxide(Ti O₂),were used to prepare photonic structures with different cell numbers,different surface thickness coefficients,and different mirror symmetric combinations,having good sample uniformity;set up a spectrum test system to test and characterize each sample,compare and analyze the results with theoretical calculations.As the number of cells increases,the experimental results are more consistent with the theoretical calculations;the measurement of samples with different surface layer thicknesses fully shows that the interface state frequency can be effectively controlled by changing the surface layer thickness.The test results of a sample containing two mirror symmetric planes indicate the existence of two interface states.The experimental results are consistent with the theoretical analysis,further confirming the feasibility of the one-dimensional mirror-symmetric photonic structure to generate the interface state.