Polarization Conversion And Perfect Absorption Based On Surface Plasmon Metamaterial

Metamaterials,composed with artificial meta-structures and novel physical properties,is a new concept in the 21 st century.Equipped with extraordinary physical properties,this new-type material can break through the limitations of the materials in nature,and provides all kinds of methods to control the propagation of electromagnetic waves,such as metalens,polarization converter,perfect absorber,invisible cloaks and other applications.These novel physical phenomena will push the development of communications,sensor,photoelectric detector,and imaging.In past years,with the gradual development and in-depth research of metamaterials,the theory and technology have become more and more developing,and its application has gradually moved from the optical fields to communication,energy,and biography,forming a series of interdisciplinary subjects.The metasurface can be regarded as two-dimension metamaterials,which can realize flexible control of electromagnetic wave about amplitude,polarization states,and propagation.Polarization converter refers to an optical device that can change the polarization direction or polarization state of incident light,such as converting x-polarized incident light into y-polarized after reflectance/transmittance.As its name implies,metamaterial perfect absorber means that the incident light interacts with the artificial resonator in a way that no reflectance and transmission occur.Therefore,incident lights were absorbed by the designed metamaterial.Strictly speaking,a perfect absorber should meet several criterions: polarization insensitivity,incident angle tolerance,and ultrawide operating band.However,metamaterial perfect absorber with specific characteristics also plays a unique role in a specific case.This thesis mainly discusses the design of artificial nanostructures with all-metal structures to give polarization converters and perfect absorbers with new physical properties,and systematically introduces their potential applications in controlling imaging,optical switching,and biosensors.The main content of the paper is arranged as follows:(1)The concept and development of surface plasmon nano-optics,and potential applications in exploring polarization converters and perfect absorbers in development of optoelectronic devices.(2)Simulation and experiment approach: 3D electromagnetic simulation software in designing artificial meta-structure,as well as the sample fabrication and the construction of the measurement setup.(3)Research about all-metal polarization converters,discuss the similarities and differences between L-shape nano-antenna and metal nanorods in controlling the polarization direction,and employ experiment to clarify numerical simulation.(4)Exploration about perfect absorber based on toridal resonance mode,which accomplished by high Q and strong absorption performance.The simulation results show that this kind of optoelectronic devices provides a new approach in biosensor,such as the change of refractive index.(5)Summarize and prospect about the research results above.