Research On Infrared Absorption Characteristic Of Metamaterial Absorber Based On MIM Structure

Infrared radiation plays a very important role in the electromagnetic wave band.Identifying the absorption characteristics on infrared radiation of an object can promote the development of infrared stealth,infrared detection,infrared thermal imaging,thermal photovoltaics and other fields.Active modulation of infrared absorption are based on the intrinsic characteristics of the material itself to infrared radiation for traditional infrared devices,thus,these devices have really limited ability to master electromagnetic waves,which leads to various problems such as narrow working band,low absorption rate and difficulty on fabrication.Metamaterials adopt the periodic arrangement of nanostructures,which can realize the electromagnetic properties that natural materials do not have.The infrared absorber based on metamaterials provides a new pathway to solve above problems,and has rapidly developed into a research hotspot in the field of artificial electromagnetic structural materials in recent years.In this paper,the optical properties of infrared absorber based on metamaterial are studied.The main contents are arranged as follows:1.An infrared dual-band metamaterial absorber with a single size is proposed.The effects of structural size and material parameters on its absorption characteristics were investigated.According to the results,a multi-size infrared dual-band metamaterial absorber based on coplanar structure is designed.The simulation results show that the absorption rate of the absorber is greater than 90% across 8.03～12.28 μm band,and the average absorption rate is as high as 97.9%.At the same time,it has a perfect narrowband absorption peak in the mid-wave infrared band.The absorber is insensitive to polarization angle and azimuth angle,which shows the optical characteristics of wide-angle and high absorption.The absorption characteristics of the absorber make it of great value in integrated devices,integrating energy collection and detector.2.An infrared dual-band broadband metamaterial absorber based on a laminated structure is used to achieve dual-band broadband perfect absorption in the mid-wave infrared and long-wave infrared bands.The simulation results show that the absorption rate of the absorber is greater than 90% in the wavelength range of 3.15～4.93 μm and 8～12.9μm,and the corresponding average absorption rates are 95.4% and 96.5%,respectively,achieving dual-band broadband absorption.The absorber also has polarization insensitive and wide-angle absorption characteristics.Dual-band broadband high absorption can be achieved simultaneously mainly due to the first-order slow-light mode and the third-order slow-light mode.The absorber has potential applications in dual-color infrared imaging,detection,passive radiation cooling and other fields.The two infrared dual-band metamaterial absorbers based on metal-insulator-metal(MIM)structure in this paper have characteristics of large absorption,simple structure and easy fabrication.The employment of Ti and Cu instead of precious metals such as Au and Ag reduces the manufacturing cost and promotes the application of MIM structure absorbers in integrated devices and dual-color infrared imaging.