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为了降低和消除光镊力谱系统中双光阱之间的干扰,进一步提高测试精度,本文对双光阱光镊系统中两光束间串扰的成因及其对力谱测量的影响展开了研究.研究发现,高倍物镜组与样品池构成的光学结构会引起光束偏振态的改变,是双光束串扰形成的主要因素;偏振分光棱镜自身的分光特性是串扰产生的另一因素;光阱捕获的微球,虽然改变了光束的形状和传播方向,但在光束串扰方面贡献很小.双光束的串扰信号叠加在探测的光强信号上,影响了光阱刚度和位移灵敏度的标定,最终导致力学测量的偏差.光镊系统中双光束的串扰量在同一次实验的一定时间内基本稳定.根据双光阱光镊系统的这一特点,本文提出了实时测量双光阱光镊系统两光阱独立存在时和同时存在时双光阱的刚度和位移灵敏度的方法,并经多次实验求平均后得到两种情况下双光阱的刚度和位移灵敏度的比值,在后续实验中,将该比值作为修正参数对实测的力谱曲线进行修正.结果表明,该方法有助于减小双光束串扰的影响,优化力谱测量结果,测试精度提高3.4!.
In order to reduce and eliminate the interference between the two optical traps in the optical tweezers force spectroscopy system and further improve the testing accuracy, the paper studies the causes of the crosstalk between the two optical beams and the influence on the force spectrum measurement. It is found that the optical structure of the high power objective lens group and the sample cell causes the change of the polarization state of the light beam and is the main factor of the formation of the double beam crosstalk. The spectral characteristic of the polarization beam splitting prism itself is another factor of crosstalk. The ball, although changing the shape and propagation direction of the beam, contributes very little to the beam crosstalk. The double-beam crosstalk signal superimposed on the detected light intensity signal affects the calibration of the optical trap stiffness and displacement sensitivity, eventually leading to mechanical measurements Of the optical tweezers system, the amount of crosstalk of the two beams in the optical tweezers is basically stable within a certain time in the same experiment.According to the characteristics of the optical tweezers system with dual optical traps, this paper presents the real-time measurement of two optical traps The existence of and simultaneous existence of double-beam trap stiffness and displacement sensitivity method, and after a number of experiments averaging obtained after two-light trap stiffness and displacement sensitive In the following experiment, the ratio was taken as the correction parameter to correct the measured force spectrum curve.The results show that this method can reduce the influence of double beam crosstalk, optimize the force spectrum measurement results and improve the test accuracy by 3.4 !