Study Of Metal/Dielectric/Metal Metamaterial Absorber Based On High-Refractive-Index

In recent years,metamaterial devices have been investigated extensively because of their unique properties and their potential applications.In 2008,Landy etc.designed a metamaterial absorber with nearly perfect narrow-band absorption in microwave band by using electric resonance and short wire,since then the absorber has been became one of the most representative research objects of metamaterials.Most of the metal materials of the previous absorber are adopted low-refractive-index metals such as Au,Ag,Al,etc.An ultra-wideband absorber based on high-refractive-index tungsten nanodisk array structure is proposed in this paper,which is composed of three layers of high-refractive-index metal/medium/high-refractive-index metal.The upper layer consists of five tungsten nanodisks?three small nanodisks and two large nanodisks?,and the middle layer isAl₂ O₃,and the bottom is a thick tungsten layer.The absorber can be achieved almost perfect ultra-broadband absorption over the range of 435nm to 1730 nm,and its thickness is smaller than the working wavelength.The proposed absorber has the advantages of ultra-broadband,polarization modes independence,etc.,and it also has good absorption performance for wide angle of oblique incidence.which greatly improves its application field.The main contents of this article are as follows:1.Firstly,the research progress and development direction of metamaterial absorber are introduced.The significance of research based on high-refractive-index metal/medium/metal metamaterial absorbers is also described.2.Introducing the basic theoretical knowledge of metamaterials involved in the research,including spoof surface plasmons,equivalent medium theory,finite difference time domain?FDTD?algorithm and FDTD Solutions simulation.3.We designed two kinds of low-refractive-index metal?Ag and Au?metamaterial absorbers with two different arrays:disk arrays and rectangular arrays.After optimizing the geometric parameters of the two array absorbers,the effects of high-refractive-index metal materials?Ni,W?on the absorption efficiency of the absorbers are analyzed and compared,and the result of the low-refractive-index metal components with low absorption rate in a certain wavelength range is verified.4.We proposed a high-refractive-index tungsten nanodisk array metamaterial absorber,and analyzed the influences of geometric parameters on the performance of the absorber in detail.The results show that the absorber can achieve high-efficiency absorption in visible and near-infrared light?the absorptivity more than 90%in the range of 435nm-1730nm?,it is insensitive to polarization modes,and the proposed absorber still has high performance absorption in visible and near-infrared light under the condition of wide angle oblique incidence.