Numerical analysis of fluid resistance exerted on vibrating micro-sphere controlled by optical radiation pressure

Shimpei Tanaka, Yasuhiro Takaya, Terutake Hayashi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


With the recent development of microfabrication technology, the measurement technology to evaluate geometric quantities is demanded to assure their accuracy. In order to measure the 3D shape of these microcomponents, a novel nano-CMM system has been developed based on an oscillated probing technique, which uses an optically trapped particle. The particle as a probe is trapped by focused laser light using an objective in the air. The trapped particle is laterally oscillated or circularly at the focal plane of the objective using AOD (acousto-optical deflector). The motion of the trapped particle is induced by a trapping force toward a focal spot and damped by the viscosity of the surrounding atmosphere. The frequency response of the oscillated particle typically agrees with the spring-mass-damper model. On the other hand the response disagrees with the theoretical curve of the model at high frequency range, i.e. 4.6% at 4000 Hz. It is considered the difference is caused from the numerical error for the fluid effect, which is given by the stokes formula 6πηr. In this report, we construct a fluid simulation using SMAC method that calculates fluid resistance against an oscillating sphere in noninertial frame of reference. The fluid effect is investigated in order to improve the model of the sphere motion. 2D simulation indicates the same tendency in frequency response of the oscillating sphere with amplitudes of 500 nm in 100-4000 Hz frequency range. 3D simulation could improve the measurement accuracy of nano-CMM system as compared with 2D simulation.

Original languageEnglish
Title of host publicationOptical Trapping and Optical Micromanipulation V
Publication statusPublished - 2008
Externally publishedYes
EventOptical Trapping and Optical Micromanipulation V - San Diego, CA, United States
Duration: Aug 10 2008Aug 13 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOptical Trapping and Optical Micromanipulation V
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

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


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