Eigenmodes of a hydrodynamically coupled micron-size multiple-particle ring
Eigenmodes of a hydrodynamically coupled micron-size multiple-particle ring
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DOI：
10.1103/physreve.76.061402
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发表时间：
2007-12-01
影响因子：
2.4
通讯作者：
Padgett, M. J.
中科院分区：
文献类型：
--
作者：
Di Leonardo, R.;Keen, S.;Padgett, M. J.
我们使用具有集成质心跟踪的连续采集、高速相机来同时测量全息光学镊子中保持的微米大小的颗粒环的位置。粒子之间的流体动力学耦合产生了一组本征模，每个本征模都独立地松弛着一个特征衰减率(本征值)，可以使用我们的位置数据来测量。尽管粒子尺寸有限，但我们发现测量的本征值与应用于二维(2D)环几何的Osee理论的数值预测值之间有很好的一致性。通过将一维周期链的本征模包裹到环上而得到的交替本征模集合，分析了粒子的运动。我们确定了周期链是环的良好近似值的模式以及不是的模式。
We use a continuous acquisition, high-speed camera with integrated centroid tracking to simultaneously measure the positions of a ring of micron-sized particles held in holographic optical tweezers. Hydrodynamic coupling between the particles gives a set of eigenmodes, each one independently relaxing with a characteristic decay rate (eigenvalue) that can be measured using our positional data. Despite the finite particle size, we find an excellent agreement between the measured eigenvalues and those numerically predicted by Oseen theory applied to the two-dimensional (2D) ring geometry. Particle motions are also analyzed in terms of the alternative eigenmode set obtained by wrapping onto the ring the eigenmodes of a 1D periodic chain. We identify the modes for which the periodic chain is a good approximation to the ring and those for which it is not.