钠纳米球壳内外介质对其吸收光谱的影响  

Influence of In-Shell and Out-Shell Media on Na Nanoshell Absorption Spectrum

作　　者：张明富 张爽爽 周芳 单馨雨 黄勇刚[1] Zhang Mingfu;Zhang Shuangshuang;Zhou Fang;Shan Xinyu;Huang Yonggang(College of Physics and Electromechanical Engineering,Jishou University,Jishou 416000,Hunan,China)

机构地区：[1]吉首大学物理与机电工程学院,湖南吉首416000

出　　处：《光学学报》2024年第11期224-231,共8页Acta Optica Sinica

基　　金：国家自然科学基金资助项目(11964010);湖南省自然科学基金资助项目(2020JJ4495);湖南省教育厅重点项目(21A0333,22A0373,22A0377);吉首大学研究生科研创新项目(Jdy22037)。

摘　　要：分别利用局域响应近似、托马斯-费米流体动力学理论和量子流体动力学理论系统研究钠纳米球壳内外介质对其吸收光谱的影响。计算结果表明,随着壳内介电常数增加,钠纳米壳表面等离激元共振模式红移,低能量模式振幅减小,高能量模式振幅增大。随着壳外介电常数增加,低能量模式红移,振幅增大,而高能量模式则没有明显变化。相比于壳外介质,壳内介质对高能量模式的影响更大,对低能量模式的影响更小。这些结果对研究钠纳米球壳吸收特性具有重要指导意义。Objective Metallic nanoshells,consisting of a metallic layer grown over a solid dielectric core,are unique nanoparticles.These particles exhibit unique optical properties,characterized by their highly tunable plasmon resonances across a wide range of frequencies in both the visible and infrared portions of the spectrum.Such properties have attracted considerable attention and are integral to various devices,such as resonant photooxidation inhibitors,optical triggers for drug delivery implants,and environmental sensors.In recent years,quantum hydrodynamic theory(QHT)has been applied to compute the absorption spectra of Na nanoshells with varying thicknesses,emphasizing the significant impact of the quantum effect within QHT on its highenergy mode.Notably,the high-energy mode predicted by QHT is significantly redshifted compared to that predicted by the local response approximation(LRA).However,both methods,for the sake of simplicity,assume that in-shell and outshell media are vacuums,thereby neglecting the influence of these media on its absorption spectrum.Consequently,this study employs QHT to investigate the effects of the in-shell and out-shell media of the Na nanoshell on its absorption spectrum.Methods Theoretically,the classical Drude model under the LRA for free electrons is typically applied to elucidate the optical response of plasmonic nanostructures.However,when the characteristic size of the nanostructure is less than 10 nm or the gap size of the nanodimers is of the order of subnanometers,the LRA becomes ineffective,and nonlocal corrections must be considered.In the context of free electron gas,the simplest corrections beyond the LRA are achieved by incorporating the Thomas‒Fermi(TF)electron pressure into a hydrodynamic-like description,known as the Thomas‒Fermi hydrodynamic theory(TFHT).However,both techniques overlook quantum effects,such as electron spillover and Landau damping,essential at nanometer scales.The QHT effectively accounts for the aforementioned quantum effect computationally.Ther

关 键 词：表面光学 表面等离激元 纳米球壳 介电环境 量子效应 

分 类 号：O436[机械工程—光学工程]