Braun Marco, Würger Alois, Cichos Frank
Molecular Nanophotonics Group, Institute of Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany.
Phys Chem Chem Phys. 2014 Aug 7;16(29):15207-13. doi: 10.1039/c4cp01560f. Epub 2014 Jun 17.
In this article we explore the dynamics of a Brownian particle in a feedback-free dynamic thermophoretic trap. The trap contains a focused laser beam heating a circular gold structure locally and creating a repulsive thermal potential for a Brownian particle. In order to confine a particle the heating beam is steered along the circumference of the gold structure leading to a non-trivial motion of the particle. We theoretically find a stability condition by switching to a rotating frame, where the laser beam is at rest. Particle trajectories and stable points are calculated as a function of the laser rotation frequency and are experimentally confirmed. Additionally, the effect of Brownian motion is considered. The present study complements the dynamic thermophoretic trapping with a theoretical basis and will enhance the applicability in micro- and nanofluidic devices.
在本文中，我们探讨了无反馈动态热泳阱中布朗粒子的动力学。该阱包含一束聚焦激光束，局部加热圆形金结构，并为布朗粒子产生排斥性热势。为了捕获粒子，加热光束沿着金结构的圆周移动，导致粒子产生复杂的运动。我们通过切换到旋转坐标系（其中激光束静止）从理论上找到了一个稳定性条件。计算了粒子轨迹和稳定点作为激光旋转频率的函数，并通过实验进行了验证。此外，还考虑了布朗运动的影响。本研究为动态热泳捕获提供了理论基础，将提高其在微纳流体装置中的适用性。
