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1999 Fiscal Year Final Research Report Summary

Dynamics and light-scattering properties of Brownian particles in suspensions under laser radiation pressure

Research Project

Project/Area Number 09450024
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Applied optics/Quantum optical engineering
Research InstitutionHokkai-Gakuen University

Principal Investigator

ASAKURA Toshimitsu  Hokkai-Gakuen University, Faculty of Engineering, Professor, 工学部, 教授 (70001188)

Co-Investigator(Kenkyū-buntansha) IWAI Toshiaki  Hokkaido University, Research Institute for Electronic Science, Associate Professor, 電子科学研究所, 助教授 (80183193)
HARADA Yasuhiro  Kitami Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80198928)
TAKAI Nobukatsu  Hokkai-Gakuen University, Faculty of Engineering, Professor, 工学部, 教授 (30001340)
Project Period (FY) 1997 – 1999
KeywordsRadiation pressure of light / Dynamic light scattering / Brownian motion / Photophoresis / Fokker-Planck equation / generalized Lorenz-Mie theory / Enhanced backscattering / fractal aggregates
Research Abstract

Dynamics and light-scattering properties of Brownian particles in colloidal suspensions under the influence of the radiation pressure force of an illuminating laser beam are investigated theoretically and experimentally.Spatial and temporal properties of coherent light multiply scattered backward by the highly concentrated system of particles with aggregations have also been investigated theoretically and experimentally. The main results are summarized in the following:
1. Dynamic behavior of the Brownian particles: Suppression of the Brownian motion of the particles in radial direction of the laser beam and induction of translational motions in the beam propagation direction are found to have dependencies on power and beam-waist radius of the laser and particle size. It is clarified from computer simulations using the Fokker-Planck equation and the generalized Lorenz-Mie theory that the changes in the dynamics of the particles in the radial and beam propagation directions are due to a … More gradient force and scattering force components of the radiation pressure of the laser beam, respectively. It is also found that, if the particle radius is larger than the beam-waist radius, velocity of the translational motion of the particle in the beam propagation direction has two maxima along the beam propagation direction and their positions are directly related to the particle size.
2. Statistical properties of the scattered light: As a result of the changes of dynamic behavior of the particles, a temporal correlation function of intensity fluctuations of the scattered light deviates from theoretical one. Degree of the deviations in the temporal correlation function is strongly dependent on the the size of the particles and the power and beam-waist radius of the laser beam. It is demonstrated that a peak intensity distribution and a temporal correlation time of the light multiply scattered backward change suddenly due to aggregation of particles in suspensions. These changes in the peak intensity distribution and the correlation time are closely related to spatial properties of the particles in both microscopic and macroscopic scales. Less

  • Research Products

    (16 results)

All Other

All Publications (16 results)

  • [Publications] Toshiaki Iwai: "Coherent backscattering of light from a polydisperse random medium as a model of fractal aggregation of particles"Proceedings of SPIE. 3252. 90-98 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Harada: "Computer simulation of dynamics and light-scattering properties of Brownian particles under the laser radiation pressure"Proceedings of SPIE. 3252. 99-106 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Katsuhiro Ishii: "Optical free-path-length distribution in a fractal aggregate and its effects on enhanced backscattering"Applied Optics. 37(21). 5014-5018 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Harada: "Dynamics and dynamic light-scattering properties of Brownian particles under laser radiation pressure"Pure and Applied Optics. 7(5). 1001-1012 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Katsuhiro Ishii: "Monitoring of the cluster growth in the colloidal suspension using a diffusive wave spectroscopic technique"Proceedings of SPIE. 3599. 76-85 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Katsuhiro Ishii: "Optical sensing of fractal aggregates of particles using backscattering enhancement"Proceedings of SPIE. 3740. 549-552 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Katsuhiro Ishii: "Correlation properties of light backscattered multiply from fractal aggregates of particles under Brownian motion"Journal of Biomedical Optics. 4(2). 230-235 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Harada: "Sizing method for biological particles in suspensions using laser trapping techniques"Proceedings of OWLS VI. (submitted). (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Iwai,K.Ishii, and T.Asakura: "Coherent backscattering of light from a polydisperse random medium as a model of fractal aggregations of particles"Proceedings of SPIE. 3252. 90-98 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Harada and T.Asakura: "Computer simulation of dynamics and light-scattering properties of Brownian particles under the laser radiation pressure"Proceedings of SPIE. 3252. 99-106 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ishii, T.Iwai, J.Uozumi, and T.Asakura: "Optical free-path-length distribution in a fractal aggregate and its effects on en-hanced backscattering"Applied Optics. 37(21). 5014-5018 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Harada and T.Asakura: "Dynamics and dynamic light-scattering properties of Brownian particles under laser radiation pressure"Pure and Applied Optics. 7(5). 1001-1O12 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ishii and T.Iwai: "Monitoring of the cluster growth in the colloidal suspension using a diffusive wave spectroscopic technique"Proceedings of SPIE. 3599. 76-85 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ishii and T.Iwai: "Optical sensing of fractal aggregates of particles using backscattering enhancement"Proceedings of SPIE. 3740. 549-552 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ishii, T.Iwai, and T.Asakura: "Correlation properties of light backscattered multiply from fractal aggregates of particles under Brownian motions"Journal of Biomedical Optics. 4(2). 230-235 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Harada and T.Asakura: "Sizing method for biological particles in suspensions using laser trapping techniques"Proceedings of OWLS VI. submitted for publication. (2000)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2001-10-23  

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