金纳米颗粒复合结构可调表面等离激元特性  

Tunable Surface Plasmon Properties of Gold Nanoparticle Composite Structure

作　　者：金晶 程旭东 周云 薛振宇 董志成 Jin Jing;Cheng Xudong;Zhou Yun;Xue Zhenyu;Dong Zhicheng(College of Science,China Jiliang University,Hangzhou 310018,Zhejiang,China;Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province,College ofInformation Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China)

机构地区：[1]中国计量大学理学院,浙江杭州310018 [2]中国计量大学信息工程学院浙江省电磁波信息技术与计量检测重点实验室,浙江杭州310018

出　　处：《中国激光》2024年第17期320-329,共10页Chinese Journal of Lasers

基　　金：浙江省自然科学基金(LY21F010010)。

摘　　要：金纳米颗粒局域表面等离子体共振峰的位置与纳米颗粒的几何形状密切相关,通过改变非球形金纳米颗粒的结构参数能调控其局域表面等离子体共振峰。建立不同形状的非球形金纳米颗粒复合结构的表面等离激元介电函数模型,利用时域有限差分法研究不同形状金纳米颗粒纵轴和横轴长度、纵横比以及间距与近场局域增强和远场散射特性的关系。结果表明金纳米颗粒的结构参数会对表面等离子体共振效果产生显著影响,可以通过改变结构参数来调控结构的表面等离子体共振特性。研究结果对于非球形金纳米颗粒复合结构表面等离子体共振峰的精确调控具有指导意义。Objective Surface plasmon resonance(SPR)is the resonance of incident light waves at the metal-medium interface with collectively oscillating electrons.Gold nanoparticles exhibit a pronounced local surface plasmon resonance effect,where the position of the local surface plasmon peak is intricately linked to the geometry of the nanoparticles.The electromagnetic properties of non-spherical metal nanoparticles demonstrate excellent controllability as their shape and size undergo variations.In single-structure gold nanoparticle sensors,the increase of the aspect ratio of gold nanoparticles improves the sensitivities of the sensors.However,there is a lack of research on the regulation of surface plasmon resonance in the composite structure.Although recent studies have shown promising outcomes by incorporating gold nanoparticles into composite structures,they lack comprehensive investigations and summaries regarding the impacts of the transverse axis length,longitudinal axis length,aspect ratio,and spacing of gold nanoparticles with different shapes on the surface of gold nanocomposite structures.Fine-tuning the geometric parameters of gold nanoparticles in the composite structure can further elevate the practical value of the composite structure.Hence,this fine-tuning demonstrates significant application potential in areas such as biosensing and detection.Methods In this study,we establish a model for the dielectric functions of composite structures of non-spherical gold nanoparticles with different shapes.The structures consist of layers from bottom to top:a 700 nm thick SiO_(2)layer,a 100 nm thick gold film,a 200 nm thick dielectric matching layer,and gold nanoparticles.Using the finite-difference time-domain(FDTD)method,perfect matched layer(PML)absorbing boundary conditions are applied at the upper and lower boundaries in the z-axis direction,and periodic boundary conditions are applied in the x-and y-axis directions.Plane waves ranging from 400 nm to 900 nm are incident from the positive z-axis.We investigate the

关 键 词：表面等离激元 非球形金属纳米结构 时域有限差分法 电场增强 

分 类 号：O539[理学—等离子体物理]