Influence of the bandwidth of an acquisition system on the trap stiffness measurement

Zan Gong*, Hongtao Chen, Shenghua Xu, Yinmei Li, Liren Lou

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


The high precision calibration of optical trap stiffness is the foundation of the weak force measurement in optical tweezers system. And the accuracy of the trap stiffness measurement is limited by the bandwidth of the acquisition system. In this article, such an influence is analyzed and discussed. First, the power spectrum of the thermal motion of a trapped bead is analyzed and the true trap stiffness is compared with the stiffness measured by a limited bandwidth acquisition system. Then the stiffness measuring process is simulated using Monte Carlo method when thermal motion analysis method is used to measure the trap stiffness. It is demonstrated that the influence of the bandwidth is related to the trap stiffness and bead diameter. And that the measured trap stiffness is greater than the true value is also demonstrated when the bandwidth of the acquisition system is not sufficient.

Original languageEnglish (US)
Pages (from-to)262-265
Number of pages4
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jun 14 2005
Externally publishedYes
EventNanophotonics, Nanostructure, and Nanometrology - Beijing, China
Duration: Nov 8 2004Nov 10 2004


  • Bandwidth
  • Optical tweezers
  • Trap stiffness

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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