高斯光束中吸收双层球形微粒的横向光俘获

为了研究吸收双层球形微粒的横向光俘获，基于几何光学模型提出了双层带吸收球形微粒的光俘获模型，对TEM₀₀模式高斯光束照射下外层有光吸收的双层电介质球形微粒受到的横向光俘获力进行了数值模拟，取得了光俘获力特性的一系列结果.结果显示，双层球形微粒的外层吸收系数对包括稳态俘获位置，峰值强度，稳态俘获的刚度等光俘获特性有很大影响.此外，内外径的比率对吸收双层球形微粒的光俘获特性也有调制性的影响.在一定条件下，带吸收的双层球形微粒可以被俘获在光轴上，也可能被俘获在中心在光轴上的圆环上. 关键词： 光俘获 几何光学模型 高斯光束 吸收双层球

Transverse optical trapping force of absorbing double-layer spherical particles in a Gaussian beam

In this paper, the transverse optical trapping of absorbing double-layer spherical particle is studied based on geometrical optics model. A model for double-layer spherical particle with optical absorption is presented. The transverse optical trapping force of a double-layer dielectric spherical particle with linear absorption in the outer layer illuminated by a focused Gaussian beam of TEM₀₀ mode is simulated numerically. Our results show that the characteristicsof optical trapping, including the stable trapped positions, the peak intensityand the stiffness of stable trapping, greatly depend on by the absorption coefficient of the double-layer spherical particle. Besides, the ratio of the inner radius to the outer radius of the particle also has modulating influence on the properties of transverse trapping. It is possible to trap transversely the double-layer spherical particle with absorption on the axis of the incident Gaussian beam and on a circle centered at the optical axis for different axial offsets of sphere center from the beam waist as well.