Design And Research Of Meta-Surface Devices

Meta-surface is a kind of two-dimensional functional material that has been manually designed.It has a very broad application prospects in today’s highly integrated multi-functional photon system.Meta-surface based on surface plasmon is an important classification in micro-nano meta-surface.It is an ideal absorbing material because of its super-thin,perfect absorption,adjustable band,etc.It is very useful in solar energy absorption,electromagnetic shielding,electromagnetic wave control and other fields.As a kind of material with less loss than metal,Fano resonances with much higher quality can be excited in dielectric metasurface in transmission systems.Fano resonance is a kind of resonance with asymmetric spectral line.It has been applied in many fields such as optical switch,optical sensor,non-linearity,etc.High refractive index dielectric materials such as silicon,indium arsenide,and gallium arsenide are widely used in micro-nano devices.It provides a possible solution for the miniaturization and high performance of photonic devices.The research and design of meta-surface devices is currently in the stage of transitioning from laboratory to widespread application,with one of the difficulties being the sensitivity of their performance to dimensional accuracy and the difficulty of precision machining complex nanoscale structures.In this paper,the two types of meta-surface devices are studied,in which the causes of the special physical phenomena are analyzed,and the performance parameters and their stability are discussed in practical application.The contents and main innovations of this study include:1.The MIM waveguide structure with asymmetric ring and dentate cavity is designed as a multi-Fano resonance system.Using the waveguide structure as a refractive index sensor,multiple detection sites can be achieved.The multi-mode coupling analysis method of the design model is simplified.The transmission spectrum of the waveguide is calculated by the multi-mode coupling theory,which is in good agreement with the simulation results.The cause of Fano resonance is analyzed by the electric field distribution of the waveguide.2.Ultra-wideband perfect absorber is designed based on three-layer step metal structure.It uses a structure with low complexity and easy preparation to achieve perfect absorption of 3690 nm bandwidth.It is also insensitive to polarization and incidence angle.3.A wide/narrow band adjustable absorber was designed based on the structure of the vanadium dioxide/gold rectangular ring.Using the temperature phase transition characteristics of vanadium dioxide,a dual narrow band absorption mode was observed at low temperatures(below 68℃).There were two narrow band absorption peaks at 298 nm and 4332 nm.At high temperatures(above 68℃),the absorption mode was broadband,with a broadband absorption rate of more than 90%at 2570 nm and a temperature change.The maximum change in absorbance is 66%.Temperature of the meta-surface is controlled by laser heating.The heating and cooling processes of the meta-surface are very short,and the wide/narrow band switching of the absorber is fast.With the improvement of meta-surface structure,the vanadium dioxide/gold adjustable absorber is more practical because of its polarization insensitivity and incident angle insensitivity.4.By introducing random errors,the stability of meta-surfaces for micro-nano fabrication process is studied,which provides possible suggestions for the design of meta-surface devices.5.In order to break the geometric symmetry in symmetrically protected BIC,a new way to break the symmetry is proposed:the refractive index is asymmetric.Compared with the traditional geometric parameters,the asymmetry of the refractive index is less affected by the processing error and can form the same quasi-BIC state as the traditional way.The sensitivity of the asymmetric refractive index structure as a refractive index sensor can reach 394 nm/RIU,the FOM value can reach 4925,and the Fano resonance peak Q value can reach 14436.The meta-surfaces designed in this paper have high stability,which provides new ideas for the design of meta-surface devices,provides new possibilities for the practicability of meta-surface devices,and has positive significance for the further integration and high performance of photonic systems.