光诱导金属纳腔的相干声学振动及应用  

Laser Excitation of Coherent Acoustic Vibrations of Metallic Nanoresonators and Their Applications

作　　者：余快 陈云高 汪国平 Yu Kuai;Chen Yungao;Wang Guoping(State Key Laboratory of Radio Frequency Heterogeneous Integration,College of Electronics and Information Engineering,Shenzhen University,Shenzhen 518060,Guangdong,China)

机构地区：[1]深圳大学电子与信息工程学院射频异质异构集成全国重点实验室,广东深圳518060

出　　处：《光学学报》2023年第16期233-252,共20页Acta Optica Sinica

基　　金：国家重点研发计划(2022YFA1404500);国家自然科学基金面上项目(12074266,12074267);广东省重点研发计划(2020B010190001);广东省科学基金面上项目(2022A1515011663,2023A1515010003)。

摘　　要：金属纳米颗粒除了用作光学谐振腔,也是一类声学谐振腔,具有非常优异的声学振动性能。本文对金属声学谐振腔的相干声学振动及应用进行了概述。首先,介绍了金属纳腔相干声学振动的超快光学激发机制,并讨论了瞬态吸收光学显微镜对单个纳腔声学振动的探测;其次,阐述了几种简单金属声学纳腔(包括纳米球、纳米棒、纳米片)的振动模式、振动频率以及它们与纳腔尺寸、形状之间的关系;然后,重点讨论了金属纳腔间的声学振动强耦合现象,从多种纳腔耦合体系的实验出发,并从理论上分析了其中的耦合模式和耦合物理机制;接下来,对高频声学纳腔的应用进行了举例分析,详细讨论了高频声学振动在纳米流体学方面的应用;最后,对高频声学纳腔的未来发展趋势与应用前景进行了展望。Significance Metal nanoparticles exhibit superior optical resonances,known as localized surface plasmon resonances,due to collective oscillations of free electrons during their interaction with incident light.These resonances enhance light absorption and scattering,making these nanoparticles highly efficient in interacting with electromagnetic waves.The tunability of plasmon resonances through nanoparticle size,shape,and composition further enhances their optical responses.As a result,plasmonic nanoparticles are valuable for applications such as sensing,imaging,and energy conversion.In addition to their optical resonances,metal nanoparticles also serve as acoustic resonators,capable of converting electromagnetic energy to mechanical energy through photoacoustic and optoacoustic effects.Excitation of metal nanoparticles by short laser pulses leads to rapid increases in electron and lattice temperatures,which generates thermal expansions and particle vibrations.The mechanical vibrations in metallic nanoresonators are influenced by factors such as nanoparticle size,shape,and surrounding environment.Accurate measurements of the acoustic vibrations provide insights into the mechanical properties of nanoresonators and the surroundings,with potential applications in nano-optomechanical devices,sensor technology,and photoacoustic imaging.The vibrational frequencies of metallic nanoresonators typically range from a few to hundreds of GHz.Ultrafast pumpprobe spectroscopy has emerged as a powerful tool for investigating these high-frequency mechanical vibrations.Due to the large absorption cross-section of plasmonic nanoparticles,it is feasible to study the acoustic vibrations in metallic nanoresonators at a single-particle level.In such experiments,a pump laser excites mechanical vibrations in single particles,and a delayed probe laser monitors the dynamics of the vibrations with high temporal resolutions.The ability to perform single-particle studies of acoustic vibrations provides new opportunities for understanding the

关 键 词：超快光谱学 金属纳腔 相干声学振动 声子学器件 强耦合 

分 类 号：O433[机械工程—光学工程]