纳秒与飞秒激光作用下纳米金棒光热效应的理论与实验研究  

Theoretical and Experimental Investigations on Photothermal Effect of Gold Nanorods Irradiated by Femtosecond or Nanosecond Laser

作　　者：赵鹏辉 冯璟 邢林庄[1] 李东[1] 陈斌[1] 廖丁莹 Zhao Penghui;Feng Jing;Xing Linzhuang;Li Dong;Chen Bin;Liao Dingying(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an Shaanxi710049 China;Department of Ophthalmology,The Second Affiliated Hospital,Xi’an Jiaotong University,Xi’an Shaanxi710004 China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049 [2]西安交通大学第二附属医院眼科,陕西西安710004

出　　处：《中国激光》2021年第22期136-144,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(51976170)。

摘　　要：纳米金颗粒可以有效增强激光诱导光学击穿效应,但不同脉冲激光下激光诱导光学击穿的机理不同。为了从微观角度揭示纳秒和飞秒激光照射纳米金颗粒过程中颗粒内部的光热转换和环境介质的变化,建立了脉冲激光加热水介质中纳米金棒的电子-声子双温度模型,结合实验研究,分析了不同激光能量密度和脉冲宽度对光热转换过程的影响,以及纳米金棒微观熔化特性的差异。结果显示,纳秒和飞秒激光照射下纳米金棒内部的电子和晶格温度的变化趋势基本一致。飞秒激光照射时纳米金棒的熔化阈值约为纳秒激光照射时的1%,纳秒激光照射时纳米金棒周围的水温更高。飞秒激光照射时纳米金棒形貌的改变主要以机械碎裂为主,而纳秒激光作用下则主要以热致纳米金棒熔化为主。Objective At present,laser-induced optical breakdown has been widely used in biological sample detection,manipulation,laser-induced breakdown spectra and laser processing of transparent media(glass,etc.).Using the local plasma resonance effect of gold nanoparticles,the laser-induced optical breakdown effect can be enhanced by gold nanoparticles.Under the laser irradiation with strong pulse energy,the morphology of gold nanoparticles may gradually change into irregular spheres with sharp angles and convex edges,leading to significant changes in their photothermal conversion abilities.From the microscopic point of view,it is of great guiding significance to reveal the photothermal conversion rule inside gold nanoparticles in the process of nanosecond or femtosecond laser irradiationand to explore the mechanism of the morphology change of gold nanoparticles under the action of two kinds of lasers.In this paper,a theoretical model of high intensity pulsed laser irradiation of gold nanorods is constructed to study the effects of laser energy density and pulse duration on the photothermal conversion process.Combined with the experimental study of laser irradiation of gold nanorods,the difference in the microscopic melting characteristics of gold nanorods under nanosecond or femtosecond laser irradiation is analyzed.Methods In this paper,the electron-phonon dual temperature model under the action of laser is used to simulate the heating process of gold nanorods in water by intense laser pulses.Firstly,the basic properties of each domain are strictly defined,including the initial temperatures of gold nanorods and surrounding environment and the selection of boundary conditions for the surrounding water.The electron and lattice temperature variations are obtained by solving the governing equations based on the two-temperature model.According to the solved values of electron and lattice temperatures,we can use the energy conservation equation of water to obtain the transient changes of water temperature along the R and Z a

关 键 词：激光技术 纳米金棒 激光诱导光学击穿 光热效应 电子-声子双温度模型 

分 类 号：R318.51[医药卫生—生物医学工程] R758.5[医药卫生—基础医学]