Design Of Metamaterial Perfect Absorber For Visible And Infrared Band

Metamaterial is a material with a periodic structure that is a artificially designed using materials already in nature.By reasonably selecting the materials used and the appropriate structure size,some unexpected characteristics that do not exist in nature can be obtained.It has a wide range of applications in electromagnetic stealth,energy harvesting,perfect lenses,etc.Metamaterial perfect absorber(MPA)is a branch of metamaterial research.By designing a reasonable metamaterial structure,it can absorb the incident light wave at a specific wavelength.With the continuous research and practical application of metamaterials,the realization of broadband absorption has become one of the research hotspots of metamaterials.Broadband absorption of light waves can greatly broaden the use scenarios,such as solar cells.In addition,we also need to study the characteristics that can achieve the absorption efficiency of metamaterial at a greater angle of incidence,and the polarization-sensitive characteristics that need to be investigated.With the improvement of the absorption effect,there are some other problems,such as improper control of the structure thickness,complicated structure design,and difficulty in actual manufacturing.Therefore,these shortcomings also need to be improved.In response to possible problems,we have summarized the previous research results.Here,two types of MPA are designed to achieve the absorption capacity covering the ultra-wide bandwidth from the visible light to the mid-infrared range.In addition,the differences in the absorption properties of the two types of metamaterials in the wide band are analyzed from the structural characteristics and the material characteristics,and then some other factors that affect the absorption rate are studied.The research work in this paper starts from the working principle of metamaterial absorption,and provides a theoretical basis for simulation analysis by introducing several common metamaterial absorption working mechanisms.The method of extracting S-parameters is used to calculate the metamaterial absorption rate.Listed the common electromagnetic simulation software,and introduced the working principle and simple use process of the software CST Microwave Studio 2019 used in this article to provide a basis for simulation analysis.First of all,this paper designs a metamaterial perfect absorber with laminated symmetric structure,which uses the combination of absorption peaks that originally belong to different wavelengths to achieve broadband absorption ofincident light in the visible light band.The polarization sensitivity of the designed metamaterial absorber and the degradation characteristics of the absorption rate at large angles were analyzed.The characteristics of the field inside the metamaterial at a specific absorption peak are calculated,and the absorption performance is proved by calculation using the principle of impedance matching.Finally,the effect of the difference in the number of structural layers on the absorption rate and absorption bandwidth is discussed to obtain the number of layers that produce the best absorption.Next,we change a way of thinking,starting from the material properties of the metal,replacing the metal used in the conventional design of metamaterials with a metal with a high complex dielectric constant ?”,to increase the loss of incident light waves and improve broadband absorption range and effect.We extend the working wavelength range from visible light to near infrared band.By designing a simple metal-dielectric-metal three-layer metamaterial absorber,we achieve a better absorption effect.The sensitivity of the metamaterial absorber to different polarizations and the absorption rate under the condition of two polarizations at large angles are also analyzed and simulated.Finally,continuing the way of using high complex permittivity metals in the previous chapter,by using another metal material and changing the overall structural size and shape,we designed a metamaterial absorber that can absorb light waves in the broadband range of the mid-infrared band.The polarization sensitivity and angular tolerance were also investigated.In addition,the effect of changes in the dimensions of different parts on the absorption properties of metamaterials was also studied.The factors affecting the absorption performance of metamaterials are obtained,and a new idea is proposed for adjusting the working range of metamaterials.