光场力的电磁理论分析  

Electromagnetic theory of optical forces

作　　者：李忠明[1,2] 张镇西[1] 

机构地区：[1]西安交通大学生物医学信息工程教育部重点实验室,生命科学与技术学院,陕西西安710049 [2]咸宁学院信息工程学院

出　　处：《量子电子学报》2007年第2期211-215,共5页Chinese Journal of Quantum Electronics

基　　金：国家自然科学基金项目(60178034);湖北省教育厅自然科学基金项目(2001B45001)资助

摘　　要：利用经典电磁理论导出光场中线性动量的守恒定律,并获得光散射力和梯度力的一般表达式,进而解释光场辐射压及尺寸远小于光波长的任意形状的生物微粒子在激光光场中所受的散射力和梯度力。理论分析表明光散射力是由于偶极子散射导致电磁波动量变化产生,而梯度力为作用在感应偶极子上的洛伦兹力,激光对微粒的作用力与光束束腰半径、粒子的大小、粒子及周围媒质的折射率和激光功率等系统参数的有关。Based on classical electromagnetic theory, the conservation law for linear momentum in .an optical field is derived. The expressions of gradient and scattering forces exerted on an arbitrary object are obtained. It validates that electromagnetic model can be used to explain fundamental of laser trapping and manipulation of living biological cells and organelles with cells. Theoretical analysis indicates that the forces acting on Rayleigh particles can be divided into two types： the scattering force which comes from electromagnetic wave momentum changes due to the scattering by a dipole and the gradient force which is equal to the Lorenz force acting on the induced dipole. And the optical forces are relative to systemic parameters including the radius of the beam waist, the relative refractive index of particle and surrounding medium, the radius of particle and laser power.

关 键 词：光的电磁理论 光场辐射力 理论分析 生物细胞 

分 类 号：O431.1[机械工程—光学工程] TN249[理学—光学]