The Design Investigations On The Plasmonic Structural Colors And The Related Metamaterial Structures

Surface plasmons?SPs?result from the electrons oscillations on a metal surface under the excitation of an external electromagnetic field.With the advancement of nanotechnology,SPs have broad application prospects in physics,biology,chemistry,energy,information and other fields.In recent years,due to the unique optical characteristics of SPs,they have attracted great attention from the scientific community in the fields of structured color materials,perfect absorbers,and sensitive sensors.This thesis mainly uses the SPs as the mechanism for experimental and theoretical research,and uses the finite-difference time-domain method to simulate its structure.The specific research content and results are as follows:Firstly,we prepared a structural color materials?SCMs?based on the surface plasmon optical two-sided effect.A four-layer structure of Si-SiO₂-Au-Si was sputtered on a glass substrate by a magnetron sputtering coating method.Gold nanoparticles?Au NPs?were obtained by annealing the Au film.The combination of the Si-SiO₂-Si structure and the Au NPs super-surface produced an optical two-sided effect of SCMs.Obviously different colors were observed on the front and back of the sample.In addition,the optical properties under different structural configurations were studied.The system has broad application prospects in the fields of displays,color filters,architecture,anti-counterfeiting labels and so on.Secondly,we proposed a perfect absorber based on elliptical nano-disks array.The finite-difference time-domain method?FDTD?method is used to simulate the structure of our design,and the structural parameters are optimized to obtain the best absorption performance.In the wavelength range from visible light to the near-infrared region,the absorption bandwidth reaches 1376 nm with the absorptivity greater than 90%,and the average absorptivity is as high as 94.6%.In addition,the ultra-wideband absorber has the characteristics of independent polarization and insensitive angle.This system has broad application prospects in the fields of solar photovoltaic power generation and infrared detection.Thirdly,we proposed a metamaterial electromagnetic wave absorber based on split-ring.It consists of a four-layer structure of SiO₂-Cr-SiO₂-Cr,and the middle two layers are a periodic array of Cr-SiO₂ split rings.The absorption bandwidth reaches3386 nm,ranging from 685 to 4071 nm,with the absorptivity above 90%.Moreover,the spectrally averaged absorption is up to 94.3%in the wavelength region from 600to 4200 nm.This system has broad application prospects in the fields of solar photovoltaic power generation,infrared detection,and thermo-electronic devices.Finally,we numerically proposed a mid-infrared absorber based on nano-cube.The absorption bandwidth reached 3059 nm in the wavelength range from 939 nm to3998 nm with a spectral absorptivity greater than 90%.The average absorption was up to 94.0%in a range of 800 nm to 4200 nm.As the oblique incidence angle increased to 60^o,the average absorption rate of the TE and TM modes reached 87.3%and 85.0%,respectively.This system has broad application prospects in the fields of infrared imaging and thermo-electronic devices.