Research On Broadband Perfect Optical Absorber And Its Performance Based On Finite Time Domain Difference Method

The study of perfect absorbing materials can be traced back to the beginning of the last century.With the discovery of relevant optical phenomena to the establishment of preliminary theories,an important branch has been formed in the field of optics.After the hard work of countless scientific researchers,What we call a perfect absorbing material is a specific material.It is a man-made material that cannot be found in nature and has special functions.A perfect absorbing material is a material that efficiently absorbs electromagnetic waves incident on its surface.To the effect of substantially non-reflection and non-transmission,the current perfect absorption material can not only extend the absorption spectrum from a single narrow band to a dual band,or even a wide band.The perfect absorption material can be used for high efficiency absorption of solar cells because of its absorption The characteristics of electromagnetic waves can also be used in the research of stealth fighters,other aspects such as blackbody radiation,biosensing,etc.This thesis is to construct a cylindrical Metal-medium-metal(MIM)array under the guidance of the theory of plasmon resonance on the simulation software,and a perfect absorption model of a cubic MIM array,introduces the relevant principles in detail,analyzes the simulation results and compares the influence of each parameter on the absorption effect Finally,the best model is obtained.The MIM model mentioned here refers to a metal-dielectric-metal sandwich model.The bottom metal is a layer that prevents transmission.The intermediate medium plays a role of absorbing energy and limiting energy in the structure.The top layer metal has a resonance effect with the incident electromagnetic wave,which produces an evanescent wave.The propagation characteristics of the evanescent wave make the high absorption rate a achievable effect.Under the model structure of this paper,after analysis of the simulation results,we obtained a wavelength from 476 nm-2492 nm.The perfect absorption structure with a wide frequency band and high absorption across a wide band of 2016 nm,the absorption is above 90%.In the future theoreticalresearch,I hope our research results can help a little.