有限远共轭显微镜光镊设计和误差分析

光镊是研究单分子生物物理特性的独特工具, 因而光镊设备的研发是一个极为重要的课题. 本文根据矩阵光学, 对基于有限远共轭显微镜的光镊操控光路进行计算, 得出了阱位径向操控和轴向操控方程, 并分析了光束调控系统、 共焦系统后置透镜和耦合透镜安装位置误差及物镜轴向位置调整对光镊阱位径向及轴向操控精度的影响. 计算结果显示, 当物镜初级像面和耦合透镜像方焦面完全重合, 光束调控系统和耦合透镜的距离误差对阱位径向和轴向操控精度没有影响. 光镊系统元器件定位不准时, 基于无限远共轭显微镜光镊的阱位径向操控误差和轴向操控误差都小于基于有限远共轭显微镜光镊的阱位径向操控误差和轴向操控误差. 当光镊耦合透镜定位误差控制在小于10 mm时, 基于有限远共轭显微镜光镊的径向和轴向操控误差分别小于5.9%和11.4%, 有限远共轭显微镜仍然存在改造为光镊的价值.本文理论为基于有限远共轭显微镜的光镊设计、改造和操控提供理论和实验指导. 关键词： 光镊 光学设计 矩阵 误差

Design and error analysis for optical tweezers based on finite conjugate microscope

Optical tweezers are unique tools for studying biophysical properties of single molecules. Design and construction of optical tweezers are very important. The optical path, the radial manipulation equation and axial manipulation equation of optical tweezers based on a finite conjugate microscope system are calculated using matrix optics. The influences of axial position adjustment of the objective, the installation location error of the coupling lens, the installation location error of the laser beam control system, and the installation location error of the confocal system lens' on radial trap position manipulation accuracy and axial trap position manipulation accuracy are analyzed. The results show that axial position adjustment of objective introduces no error in radial and axial trap position manipulation. The misalignment of laser beam control system has no effect on the radial manipulation, nor on axial manipulation when the coupling lens maintains alignment. It is concluded that misalignment of components of optical tweezers based on a finite conjugate microscope system has a greater effect on trap position manipulation error than misalignment of components of optical tweezers based on a infinite conjugate microscope system. The radial trap position manipulation error is less than 5.9% and the axial trap position manipulation error is less than 11.4% when the coupling lens installation location error is less than 10 mm. It is shown that optical tweezers can be modified from a finite conjugate microscope system. The formulations provide the basis for theoretical analysis of experimental alignment and adjustment.
Keywords： optical tweezers optical design matrix error