对微小力的测量是光镊系统的重要功能。主要研究了进行微小力测量时所需的重要参数――光阱刚度与实验条件的依赖关系。在以He-Ne激光器为光源的光镊系统中,得到了光阱刚度随着阱位距离样品池底面高度的提升而减小,随着被捕获小球直径的增加而减小,以及光阱刚度与激光功率具有线性的依赖关系等经验规律,并作了定性的讨论。最后给出了该系统所能达到的测力精度和测力范围。

The measurement of tiny force is an important function of the optical tweezers, for which the trap stiffness plays a key role in the measurement. In this paper, the results of the experimental study on the regulation are reported that the trap stiffness changes with experimental conditions. The results show that the trap stiffness is linearly dependent on the laser power and decreases with the trap height increasing of the bead. In addition, it decreases along with the diameter increase of the trapped bead. The results are qualitatively discussed. The accuracy and range of force measurement are also analyzed.