中文摘要：

光镊技术被广泛应用于许多生物领域。光镊本身结构简单，用单光束就可以捕获单个粒子，但对光阱力的精确计算却存在一定的难度。可以用一些近似的方法如几何光学或瑞利假设分析光阱力，但这些方法仅能在特定限制条件下适用。文中把电磁散射理论作为一种通用的方法来解决光阱力的计算问题。论述了如何使用T矩阵方法进行光阱力计算。计算结果为实验系统参量的选择提供了理论依据。

英文摘要：

The optical tweezers is widely used in many biological applications. Despite the apparent simplicity of a laser trap, a single particle is trapped with a single beam, exact calculation of the optical forces on particles is very difficult. Calculations can be performed by using some approximate methods such as Ray-Optics and Raleigh hypothesis, but these are only applicable within their ranges of validity. We can obtain a general theory for laser trapping by apply- ing the electromagnetic scattering theory. In this paper, we describe how the T-matrix approach can be used to computer optical trapping force. According to the simulation results, we can easily choose parameters of the trapping system.