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

激光辐射压力下悬浮液中布朗粒子的动力学和光散射特性

• 批准号: 09450024
• 负责人: ASAKURA Toshimitsu
• 金额: $ 6.08万
• 依托单位: Hokkai-Gakuen University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450024/
• 关键词: Radiation pressure of light; Dynamic light scattering; Brownian motion; Photophoresis; Fokker-Planck equation; generalized Lorenz-Mie theory; Enhanced backscattering; fractal aggregates; Monte-Carloシミュレーション

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

在理论上和实验上研究了胶体悬浮液在胶体悬浮液中的动力学和光散射特性。相干光的固定光乘积和临时特性由高度浓缩系统与聚合的高度浓缩系统进行了研究。布朗颗粒的动态行为：抑制激光束的径向方向的颗粒的布朗运动，并在梁传播方向上诱导翻译运动，对激光和粒径的功率和梁腰半径具有依赖性。使用Fokker-Planck方程和广义的Lorenz-Mie理论从计算机模拟中阐明了它，即径向和束传播方向中颗粒动力学的变化是由于…更梯度的力量和激光束辐射压力的渐变力和散射力成分所致。还发现，如果粒子半径大于梁腰半径，则粒子在梁传播方向上的平移运动的速度沿梁传播方向具有两个最大值，并且它们的位置与粒度直接相关。2。散射光的统计特性：由于颗粒的动态行为的变化，散射光的强度波动的暂时相关函数与理论相关的临时相关函数。临时相关函数中的出发程度在很大程度上取决于颗粒的大小以及激光束的功率和束腰半径。事实证明，由于悬浮液中颗粒的聚集，峰强度分布突然突然散布向后变化。这些变化的峰强度分布和相关时间与微观和宏观尺度中颗粒的空间特性密切相关。较少的

项目成果

K.Ishii: "Optical free-path-length distribution of in a fractal aggregate and its effect on enhanced backscattering" Applied Optics. 37(21). 5014-5018 (1998)

K.Ishii：“分形聚合中的光学自由程长度分布及其对增强后向散射的影响”应用光学。

Yasuhiro Harada: "Sizing method for biological particles in suspensions using laser trapping techniques"Proceedings of OWLS VI. (submitted). (2000)

Yasuhiro Harada：“使用激光捕获技术对悬浮液中的生物颗粒进行分级方法”OWLS VI 论文集。

T. Iwai: "Space-time statistics of the coherent light backscattered from fractal and nonfractal random media with absorption" Proceedings of SPIE. 2982. 104-105 (1997)

T. Iwai：“具有吸收作用的分形和非分形随机介质反向散射的相干光的时空统计”SPIE 论文集。

Katsuhiro Ishii: "Monitoring of the cluster growth in the colloidal suspension using a diffusive wave spectroscopic technique"Proceedings of SPIE. 3599. 76-85 (1999)

Katsuhiro Ishii：“使用扩散波光谱技术监测胶体悬浮液中簇的生长”SPIE 论文集。

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)

原田泰弘：“激光辐射压力下布朗粒子动力学和光散射特性的计算机模拟”SPIE 论文集。