光镊驱动微转子(英文)

Driving microrotor by using optical tweezers

光镊技术已经成功应用于光学和微功能器件,但是,对光镊驱动复杂微转子所建模型尚不成熟。为了分析光镊的光驱动力和力矩,基于矩量法建立了一种新模型。基于此种模型的分析结果表明改变环境参量是提高光镊工作效率的方法之一,如微转子转动速率与光镊的激光功率成正比,与束腰半径成非线性关系。另一种可以大幅度提高光镊工作效率的方法是改变微转子的形状,数据表明"万字"形微转子的转动效率是相同尺寸的"十字"形转子转动效率的10-7倍。此外,通过解析力场的分布状态,可得到光压力的主要作用面,为今后的微转子设计提供依据。新模型的另一个优点是耗费时间较少,对于模拟光镊驱动微功能器件具有通用性和柔性。

Optical tweezers have been successfully used in various scientific and engineering fields such as optics and microactuators. However, there is still a lack of a sophisticated model for optical tweez ers on driving complex microrotors. In this paper, a novel model for optical tweezers is presented to calculate the optical force and torque based on the moment method. A numerical simulation of this model shows that one of the methods to improve the efficiency of an optical tweezer is to change vari ant conditions,such as the microrotor＇s speed is in proportion to the laser＇s power and has a nonlinear relation with the beam＇s waist. The other method to improve the efficiency for the optical tweezer is to change the microrotor＇s configuration. The results show that rotor speed of the microrotor is about 10^-7 as large as that of the cross-shaped rotor. Furthermore, through analyzing the force placement, it is convenient to find the main surfaces that the optical forces act on, which can provide a foundation for the design of microrotors in the future. This model also has advantages in flexibility and universal ity in the optical force simulation of microactuators.