Design And Fabrication Of Plasmonic Artificial Microstructures And Their Optical Effects

For nearly half a century,with the rapid development of micro-nano processing and precision preparation technology,the regulation of light-substance interaction and related applications at the micro-nano scale have become an important research hotspot in current materials science.In particular,because the metal micro-nano structure can support Localized Surface Plasmons Resonance(LSPR),the capture and manipulation of light has the characteristics of sub-wavelength and greatly enhanced local field,which attracts the research interests of many researchers in materials science,information science,energy science,life science and their intersecting fields.In fact,after nearly two decades of development,metal micro-nano structures have shown great application potential in sub-wavelength optical communications,biochemical monitoring,national defense security and environmental monitoring.The surface-enhanced Raman Scattering(SERS)effect based on the metal microstructure is a typical example in the research on the mechanism and application of trace detection of substances.On the other hand,the emergence of new materials(graphene,black phosphorous,etc.),due to their special electronic structure,also provides optical researchers with new exploration directions for light field regulation.For example,due to the excellent light,electrical and mechanical properties of graphene,in recent years,people have fully integrated it with the concept of artificial optical microstructures to achieve super-strong electromagnetic performance control,especially with outstanding advantages in tunable sensors and flexible display devices.This paper mainly studies the excitation and regulation of Localized Surface Plasmon Resonance of materials such as aluminum and graphene,and on this basis,explores the effects of ultraviolet Surface Enhanced Raman Scattering and ultra long wavelength broadband optical absorption.The main research content includes the following two aspects:1.Controlled large-area self-organization techniques for different sizes of monodisperse polystyrene(PS)colloidal microspheres were developed,and metallic aluminum(Al)nanotriangular particle arrays structures were prepared by using the template replication technique of two-dimensional colloidal crystals in combination with physical deposition methods,through the self-built micro-area dark-field scattering spectroscopy system,combined with numerical simulation,in-depth study of its plasmon characteristics in the ultraviolet band.Considering the chemical instability of aluminum,we propose to clad it with ultrathin diamond-like(ta-C)high dielectric films.This ultra-thin dense surface high-dielectric modification has two functions: first,it can passivate the surface oxidation process of aluminum,and second,it can realize the nondestructive transfer of electromagnetic filed hot spots from the surface of the metallic aluminum to the dielectric surface.We use an array of metallic aluminum nanoparticles coated with 1 nm thick ta-C high dielectric film as a substrate to explore its ultraviolet SERS effect and application prospects.2.Using coupled-mode theory combined with numerical calculations,we investigate the plasmonic properties of graphene nanoparticle array structures and propose a novel scheme for the realization of broadband full absorption in graphene microstructures.Firstly,the light scattering properties and local light field characteristics of single-layer double graphene disc structure are systematically studied,and a scheme based on the anti-Hermitian coupling effect to eliminate the mode splitting caused by the inter-disk coupling effect is proposed to achieve the "decoupling" spreading of the double-disk resonance peak;on this basis,the single-layer three-disk graphene and even the multi-disk array structure are designed to achieve the broadband absorption of single-layer graphene(the absorption bandwidth of the dual-disk system exceeds 90% width is 0.2 THz,the three-disc graphene system is 0.4 THz,and the four-disc graphene system reaches ?0.6 THz)..In order to further extend the bandwidth at the limited spatial scale of the absorber,we propose an effective graphene disc array stack structure to achieve a further enhancement of the high absorption bandwidth with insensitivity to the incident light angle,and the paper explores numerically the structural fault tolerance of this system.