Zhou Jin-Hua, Ren Hong-Liang, Cai Jun, Li Yin-Mei
Department of Astronomy and Applied Physics, University of Science and Technology of China, Hefei, Anhui, China.
Appl Opt. 2008 Nov 20;47(33):6307-14. doi: 10.1364/ao.47.006307.
Traditional solid geometry ray-tracing method is complex in analyzing the orientation of gradient forces and calculating incident angle of optic rays upon a microsphere. We present a new ray-tracing methodology based on spatial analytic geometry in the ray-optic model. For a single ray upon a microsphere, the directions of transmission and trapping forces are depicted by spatial vectors in a Cartesian coordinate system. At the same time, the polarized direction of a single focused ray can be transformed by a matrix of rotational coordinates. According to the relations of vectors, the trapping forces can be expressed identically. We use this new method to discuss differences of trapping forces in the cases of various states of unpolarized and polarized beams, and also show the reasons for differences in transverse force between measurement and theoretical results. Our simulative results show that this method can be applied identically to calculating both transverse and axial trapping forces, and also for different polarizations of a laser beam.
传统的立体几何光线追踪方法在分析梯度力的方向以及计算光线在微球上的入射角时较为复杂。我们在光线光学模型中提出了一种基于空间解析几何的新光线追踪方法。对于微球上的单条光线，透射力和捕获力的方向在笛卡尔坐标系中由空间向量描述。同时，单条聚焦光线的偏振方向可通过旋转坐标矩阵进行变换。根据向量关系，捕获力可以相同的方式表示。我们使用这种新方法来讨论非偏振光和偏振光各种状态下捕获力的差异，并且还展示了测量结果与理论结果之间横向力差异的原因。我们的模拟结果表明，该方法同样可用于计算横向和轴向捕获力，以及激光束的不同偏振情况。
