非局域完美吸收薄膜的设计与仿真  

Design and Simulation of Nonlocal Perfect Absorption Thin Film

作　　者：刘建晓[1] 张丽[2] 杜晶晶 刘啸岚 孟令辉 Liu Jianxiao;Zhang Li;Du Jingjing;Liu Xiaolan;Meng Linghui(Department of Physical and Electronic Information,Hengshui University,Hengshui 053000,Hebei,China;Department of Applied Chemistry,Hengshui University,Hengshui 053000,Hebei,China)

机构地区：[1]衡水学院物理与电子信息系,河北衡水053000 [2]衡水学院应用化学系,河北衡水053000

出　　处：《激光与光电子学进展》2022年第21期248-253,共6页Laser & Optoelectronics Progress

基　　金：河北省自然科学基金(F2019111025,F2021111001);河北省教育厅科学技术研究项目(BJ2020206);衡水学院院级课题(2021ZR27,2021ZR36)。

摘　　要：时域有限差分(FDTD)方法在计算金属纳米结构的非局域特性时,往往需要更小的空间离散步长,当模型尺寸较大时会给计算带来困难。而描述金属非局域介电特性的流体力学模型由于纵向波矢的引入,给传输矩阵法(TMM)等半解析方法的运算造成不便。因此,提出了一种结合FDTD与TMM求解纳米金属非局域薄膜吸收率的方法。采用FDTD方法获得金属的反射系数和透射系数,并反演得到非局域金属的等效介电常数。将等效介电常数及模型参数代入TMM中,计算出完整结构的电磁特性。结果表明,该方法能很好地解决FDTD离散网格过小造成的内存不足和TMM中纵向波矢带来的计算复杂问题,且能快速完成分层纳米结构反射率、透射率和吸收率的计算。Finitedifference timedomain(FDTD)methods often require smaller spatial discrete steps when calculating the nonlocal properties of metal nanostructures,which brings difficulties to the calculation when the model size is large.However,due to the introduction of longitudinal wave vector,the hydrodynamic model describing the properties of the metal nonlocal property is inconvenient for the calculation of semianalytical methods such as the transfer matrix method(TMM).Therefore,a method combining FDTD and TMM to solve the absorptivity of nanometal nonlocal thin films is proposed in this paper.The reflection coefficient and transmission coefficient of the metal are obtained by the FDTD method,and the equivalent dielectric constant of the nonlocal metal is obtained by inversion.Substitute the equivalent permittivity and model parameters into the TMM,and the electromagnetic properties of the complete structure are calculated.The results show that this method can solve the problem of insufficient memory caused by small grid of FDTD and the computational complexity caused by longitudinal wave vector in TMM,and calculations of reflectivity,transmittance,and absorptivity of layered nanostructures can be performed quickly.

关 键 词：薄膜 等效介电常数 非局域 金属纳米结构 

分 类 号：O436[机械工程—光学工程]