Study On Light Absorption Effect Of Artificial Microstructures

With the development of science and technology society,energy depletion and environmental pollution have become two major problems that perplex human development.Light has the characteristics of sustainability and low pollution,which makes people turn their attention to light energy.How to detect and collect light has become the primary premise of using light.Traditional optical detection and optical absorption devices are limited by the properties of the materials,which have strict requirements on the optical parameters and geometric parameters of the materials,which limits the further development of optical detection and optical absorption research.Artificial Microstructure materials,which can realize the advantages of subwavelength size and wide angle absorption,provide a new development direction for light detection and light absorption.With the help of artificial microstructure metamaterials,people can design light absorbers with good absorption efficiency.In optoelectronic devices,broadband light absorbers are generally used to absorb light,while narrow-band absorbers are generally used as detection means to detect some light,which are extremely important for light absorption and utilization.Based on the above requirements,two kinds of light absorbers are designed by using finite element method:(1)Research on narrow band light absorber based on traditional precious metalsIn this part of the work,we designed a sandwich structure narrow-band light absorber based on traditional materials such as precious metal silver and silicon dioxide.The maximum absorption efficiency is more than 95% and the half maximum width is 5nm.In this part,with the help of the distribution of electric field,the physical mechanism of narrow band absorption is explored,and the influence of different parameters on the absorption efficiency is analyzed.The structure of the absorber is simple and highly symmetrical,so it is insensitive to the polarization of light wave and has good application potential in light detection.(2)Research on broadband light absorber based on grapheneIn this work,we designed a broadband light absorber with sandwich-like structure based on two-dimensional material graphene,traditional precious metal material silver and silicon dioxide,which can cover the visible light band,and the maximum absorption efficiency reaches 99%.Similar to the narrow-band light absorber,we also explore the physical mechanism of light absorption and the influence of parameters on its absorption performance.Because the absorber covers the visible light band,it has good potential in the absorption and utilization of visible light.With the help of finite element method(FEM),the modeling and numerical analysis of the two kinds of light absorbers are realized,and the working principle of the two kinds of light absorbers is analyzed by analyzing their electric field distribution;in addition,various parameters that may affect the absorption effect were explored.The ultra narrow band absorber realizes the narrow band absorption of light in the visible range,which makes it have the potential of application in photodetectors;The broadband light absorber based on graphene achieves the design goal of perfect absorption of light in the visible light range(the absorption rate in the visible light range is more than 80%),which further increases its absorption and utilization potential in the visible light range.