以射线光学模型为基础,对会聚高斯激光束中微粒所受轴向力进行了计算.数值计算的结果表明,束腰越小捕获越稳定;相对折射率必须大于1并存在一个最佳相对折射率;激光波长、粒子半径以及激光功率也对捕获力有重要影响.数值计算和分析为搭建光镊仪器选取系统参数提供必要的理论依据.
The axial force exerted on a micro-particle in the focused Gaussian laser beam is calculated by using the Ray-Optic Model. The calculated results show that the smaller the radius of the beam waist is, the stabler the trapping of the micro-particle is. And by analysis, we find that the relative refractive index must be greater than 1. There is an optimum relative refractive index. The wave length, the size of micro-particle and the laser power have important effects on the axial trapping force.