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Dsign Of Broadband Nanoantenna And Absorber Based On Surface Plasmon Polaritons

Posted on:2018-10-18Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2348330536959929Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
Surface plasmon polaritons(SPPs)are the electromagnetic wave that generated by the interaction between the free electron in the surface and the incident wave when the electromagnetic wave is incident on the surface of the metal.Researchers have been studying for more than 100 years.Using the SPPs model,people can achieve the conduction,focusing and enhancement of the light field at the nano-dimensional scale.Therefore,the surface plasmon polaritons in the micro-nano optical devices and sensors and other fields also have a wide range of applications.In recent years,researchers have used the near-field enhancement of SPPs to make optical absorbers,and their properties have been studied extensively.Nowadays,there are some optically absorbing been proposed,but most of these structures have some shortcomings such as resonance points are few,absorption bandwidth is not wide,the absorption efficiency is not high and so on.Therefore,aiming at this problem,this paper explores the near-field enhancement mechanism of SPPs,the wide-band,high-absorption nanoantenna and absorber is designed,and studies and analyzes their absorption characteristics by FDTD method.The main work is as follows:Firstly,the slot Yagi-Uda nanometer optical antenna based on the excitation principle of surface plasmon polaritons was designed and the absorption characteristics of the antenna array was studied.From the radiation characteristics of the Yagi-Uda antenna unit,the conditions and influencing factors of the SPPs of the antenna were studied.The antenna far field and near field characteristics are used to guide the design of the antenna array,and analyze its absorption characteristics.The study of the far field radiation characteristics of the antenna unit shows that,with the slot spacing increases,the antenna pattern appears multi-sidelobe and a new radiation pattern.Further analysis found,the new radiation pattern is derived from the high order mode of localized surface plasmons.Through the study of the absorption characteristics of the antenna array,the antenna array has good absorption properties in the waveband of 400-1500 nm,and its average absorption rate can reach 60%.The absorptivity of the slot is affected by the gap spacing.With the increase of the slot spacing,the absorptivity shows a trend of rising.In addition,the absorption band of antenna array can adjust by the thickness of the antenna unit.Secondly,we design metamaterial solar absorber and metamaterial nano ring-pillar absorber based on the modeling of the equivalent circuit and multilayer waveguide and resonator cavity structure to improve the absorptivity and absorption bandwidth.The influence of the geometric parameters on the absorptive performance of the absorber is investigated,and the influence of the polarization angle and the incident angle of the incidentlight under the wide band of the two absorbers is also analyzed.It can be seen that the two absorbers proposed in this paper have a wide absorption band,and the absorptivity is less impact by the polarization angle and the incident angle,and the absorptivity is high.Furthermore,we also analyzed the absorption mechanism of the two absorbers by the electric field distribution and the magnetic field distribution.The results show that the average absorptivity of the metamaterial solar absorber can reach 94% in the waveband of400-1500 nm.We attribute the perfect absorbing property of this absorber to the synergistic effect of the slow-wave effect and the local surface plasmon resonance.In addition to the slow-wave effect and the local surface plasmon resonance,there Fabry-perot resonance interaction of these features makes the average absorptivity of metamaterial in the300-2000 nm waveband can maintain 95%.The nanoantenna and absorber designed in this paper have high absorptivity and good absorption characteristics in the waveband of visible and near-infrared.The results of this study have certain reference value for realizing the wide-band and high-absorption solar nanobelts,and provided the idea of clean energy efficient absorption problem.
Keywords/Search Tags:Surface plasmon polaritons, Finite difference time domain, Slot Yagi-Uda nanoantenna, Metamaterial absorber, Absorption characteristics
PDF Full Text Request
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