中国物理B ›› 2015, Vol. 24 ›› Issue (11): 118703-118703.doi: 10.1088/1674-1056/24/11/118703

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

In situ calibrating optical tweezers with sinusoidal-wave drag force method

李迪a, 周金华a, 呼新尧a, 钟敏成a, 龚雷a, 王自强a, 王浩威a, 李银妹a b   

  1. a Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China;
    b Hefei National Laboratory for Physical Sciences at the Microscale, Hefei 230026, China
  • 收稿日期:2015-04-30 修回日期:2015-06-15 出版日期:2015-11-05 发布日期:2015-11-05
  • 通讯作者: Li Yin-Mei E-mail:liyinmei@ustc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11302220, 11374292, and 31100555) and the National Basic Research Program of China (Grant No. 2011CB910402).

In situ calibrating optical tweezers with sinusoidal-wave drag force method

Li Di (李迪)a, Zhou Jin-Hua (周金华)a, Hu Xin-Yao (呼新尧)a, Zhong Min-Cheng (钟敏成)a, Gong Lei (龚雷)a, Wang Zi-Qiang (王自强)a, Wang Hao-Wei (王浩威)a, Li Yin-Mei (李银妹)a b   

  1. a Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China;
    b Hefei National Laboratory for Physical Sciences at the Microscale, Hefei 230026, China
  • Received:2015-04-30 Revised:2015-06-15 Online:2015-11-05 Published:2015-11-05
  • Contact: Li Yin-Mei E-mail:liyinmei@ustc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11302220, 11374292, and 31100555) and the National Basic Research Program of China (Grant No. 2011CB910402).

摘要: We introduce a corrected sinusoidal-wave drag force method (SDFM) into optical tweezers to calibrate the trapping stiffness of the optical trap and conversion factor (CF) of photodetectors. First, the theoretical analysis and experimental result demonstrate that the correction of SDFM is necessary, especially the error of no correction is up to 11.25% for a bead of 5 μm in diameter. Second, the simulation results demonstrate that the SDFM has a better performance in the calibration of optical tweezers than the triangular-wave drag force method (TDFM) and power spectrum density method (PSDM) at the same signal-to-noise ratio or trapping stiffness. Third, in experiments, the experimental standard deviations of calibration of trapping stiffness and CF with the SDFM are about less than 50% of TDFM and PSDM especially at low laser power. Finally, the experiments of stretching DNA verify that the in situ calibration with the SDFM improves the measurement stability and accuracy.

关键词: optical tweezers, trapping stiffness calibration, conversion factor, drag force method

Abstract: We introduce a corrected sinusoidal-wave drag force method (SDFM) into optical tweezers to calibrate the trapping stiffness of the optical trap and conversion factor (CF) of photodetectors. First, the theoretical analysis and experimental result demonstrate that the correction of SDFM is necessary, especially the error of no correction is up to 11.25% for a bead of 5 μm in diameter. Second, the simulation results demonstrate that the SDFM has a better performance in the calibration of optical tweezers than the triangular-wave drag force method (TDFM) and power spectrum density method (PSDM) at the same signal-to-noise ratio or trapping stiffness. Third, in experiments, the experimental standard deviations of calibration of trapping stiffness and CF with the SDFM are about less than 50% of TDFM and PSDM especially at low laser power. Finally, the experiments of stretching DNA verify that the in situ calibration with the SDFM improves the measurement stability and accuracy.

Key words: optical tweezers, trapping stiffness calibration, conversion factor, drag force method

中图分类号:  (Optical trapping)

  • 87.80.Cc
42.50.Wk (Mechanical effects of light on material media, microstructures and particles) 87.14.gk (DNA)