Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
Proc Natl Acad Sci U S A. 2017 Oct 17;114(42):11087-11091. doi: 10.1073/pnas.1714953114. Epub 2017 Oct 2.
We examine the motion of periodically driven and optically tweezed microspheres in fluid and find a rich variety of dynamic regimes. We demonstrate, in experiment and in theory, that mean particle motion in 2D is rarely parallel to the direction of the applied force and can even exhibit elliptical orbits with nonzero orbital angular momentum. The behavior is unique in that it depends neither on the nature of the microparticles nor that of the excitation; rather, angular momentum is introduced by the particle's interaction with the anisotropic fluid and optical trap environment. Overall, we find this motion to be highly tunable and predictable.
我们研究了在流体中周期性驱动和光镊捕获的微球的运动，发现了丰富多样的动力学状态。我们通过实验和理论证明，在二维中，微球的平均运动很少与施加力的方向平行，甚至可以表现出具有非零轨道角动量的椭圆轨道。这种行为是独特的，因为它既不取决于微粒子的性质，也不取决于激励的性质；相反，角动量是由粒子与各向异性流体和光镊环境的相互作用引入的。总的来说，我们发现这种运动具有高度的可调节性和可预测性。
