悬浮微粒的光学捕获与光谱技术研究进展  

Progress in Optical Trapping and Spectroscopic Measurements of Airborne Particles

作　　者：钟航 陈钧 陈骏 廖俊生[2] Zhong Hang;Chen Jun;Chen Jun;Liao Junsheng(Science and Technology on Surface Physics and Chemistry Laboratory,Mianyang 621908,Sichuan,China;Institute of Materials,China Academy of Engineering Physics,Mianyang 621907,Sichuan,China)

机构地区：[1]表面物理与化学重点实验室,四川绵阳621908 [2]中国工程物理研究院材料研究所,四川绵阳621907

出　　处：《中国激光》2024年第3期207-224,共18页Chinese Journal of Lasers

基　　金：中国工程物理研究院统筹规划项目;国家自然科学基金(22102162);国家重点研发计划(2017YFE0301506)。

摘　　要：光学捕获经过近几十年的发展,从光学悬浮到紧密聚焦的单光束光镊再到最近发展的多种类型的光学阱,已经可以捕获包括碳、金属氧化物、花粉、孢子、无机/有机液滴等多种不同类型的粒子,结合拉曼光谱、腔衰荡光谱或激光诱导击穿光谱可以获取悬浮微粒在原生状态下的物理和化学信息,并可以实现受控气氛环境下单粒子的化学反应研究。首先,本文根据微粒的吸光性对空气中微粒的光学捕获力的来源进行了介绍,透明微粒主要受辐射压力的作用,吸光微粒主要受光泳力的作用;然后,根据光学捕获力的不同对单光束、双光束、高斯光束和空心光束等光学捕获设计进行分类介绍;最后,综述了光学捕获与光谱技术结合起来用于单粒子研究的最新进展,并讨论了光学捕获拉曼光谱面临的挑战。Significance Since Arthur Ashkin first demonstrated the ability to optically levitate and trap particles,optical tweezers and optical trapping have been applied in the physical,chemical,biological,material,and atmospheric sciences.Optically trapped microparticles in air are more likely to be affected by external disturbances,such as vibration or airflow,than those in liquid,which makes them difficult to trap in air.Recently,technology for optical trapping in air was developed.The gradient force generated by a high-focus laser and the photophoretic force resulting from thermal processes play dominant roles in the optical trapping of particles in air.When the particles are trapped,their physical and chemical properties can be studied using spectroscopic techniques.In this paper,the principles and experimental devices of the optical trapping of airborne particles are introduced,and the applications,progress,and challenges of optical trapping and laser spectroscopy are reviewed.Progress When a photon interacts with a particle,the partial momentum of the photon is transferred to the particle,which forms the scattering and gradient forces,where the gradient force is used to trap the particle.For r≫λ(particle radius,r;laser wavelength,λ),the ray optics model can be used to calculate the two forces(Fig.1).For r≪λ,the Rayleigh scattering model is often used.In addition,the absorbing particles will also be trapped by the photophoretic force,which results from thermal processes.A single-Gaussian-beam trap using a tightly focused single beam can trap a particle in three dimensions.It employs a high numerical aperture(NA)objective,which provides a strong gradient force at low laser power.However,the single-Gaussian-beam trap has a very short working distance,which limits its compatibility with other measuring techniques.The two counter-propagating beams can balance the scattering force and retain the gradient force so that the dual-Gaussian-beam trap can obtain a longer working distance(Fig.2).A single-beam photophoret

关 键 词：光谱学 光镊 光学捕获 单颗粒 气溶胶 

分 类 号：O436[机械工程—光学工程]