Study On The Principle And Fabrication Of Electromagnetic Manipulation Devices Based On Reflective Metasurface

For a long time,people devoted to exploring the interactions between the electromagnetic(EM)wave and materials,and artificially manipulating the generation,propagation and reception of EM wave by designing devices or materials.With the rapid development and wide application of optical instrument technology,a new research field of EM waves manipulation based on artificial subwavelength structure(metamaterials)has gradually emerged.Metamaterials possess the extraordinary ability to efficiently modified the polarization,amplitude and phase of EM waves,which greatly expanded the interactions between EM waves and substance.Recently,metasurface,a specific 2D metamaterial,has become a research hotspot and development trend of metamaterial and EM manipulation owing to the excellent features of thin thickness,low profile and simple fabrication process,which plays a important role in detection,sensing,stealth,optical information transportation and storage,etc.In this paper,with the support of national 973 program and national natural science funds,the principle of metasurface in manipulating EM waves was deeply investigated.Aiming at the shortcomings of low efficiency,limited bandwidth,lack of dynamic,and difficulty in fabrication,we introduced special resonance mode,design method,phase-change materials and fabrication technology to realize high efficiency,flexible bandwidth modulation,dynamic manipulation and low-cost fabrication.The main research work are as follow:(1)The Fano resonance is introduced by constructing an asymmetric metasurface,which solves the problem of low quality factor in plasmon resonance due to the metal loss in the visible and near-infrared region.A design of narrowband absorber is proposed,which is demonstrated by simulations.Furthermore,the sensing features of narrow band absorber are investigated.(2)Relying on the catenary electromagnetic(EM)field and transmission line line,a mathematical and physical model for metasurface-based EM devices is eatablished,and an anlytical method is proposed to simplify the design.Combining the anlytical method and dispersion engineering to extend the bandwidth,an absorber based on multi-layer metasurface is designed to realize ultra-broadband high-efficient THz absorption,which is experimentally demonstrated.(3)A fabrication method based on shadow mask fabrication and SP lithography technique is proposed to develop the large-area and low-cost fabrication of metasurface-based EM manipulation device with the feature size of nanometers.As proof-of-concept,a multi-spectral manipulation material based 100nm-width 2D nanoslits is designed,and the large-area and low-cost fabrication is successfully achieved by the proposed method.(4)A switchable wavefront manipulations are demonstrated numerically and experimentally via the combination of plasmonic metasurfaces with phase change materials(PCMs).As a proof-of-concept,metasurface with switchable EM response in two states of PCMs was demonstrated in near and middle infrared region.Morever,metadevices possessing switchable wavefront manipulation are achieved,which is exprimentally demonstrated in middle infrared region.