Measurements of the force fields within an acoustic standing wave using holographic optical tweezers
Measurements of the force fields within an acoustic standing wave using holographic optical tweezers
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DOI：
10.1063/1.4872462
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发表时间：
2014-04-21
影响因子：
4
通讯作者：
Drinkwater, B. W.
中科院分区：
文献类型：
--
作者：
Bassindale, P. G.;Phillips, D. B.;Drinkwater, B. W.
利用全息光镊产生的光阱，直接测量了声驻波器件中微球所受的力。在三维空间中被光学捕获的微球可以通过声学装置移动以测量作用在其上的力。当微球受到声学力时，其平衡位置被移位到声学力和光学力平衡的位置。一旦光学捕获刚度已经被校准，观察该位移使得能够直接测量作用在微球上的力。所测量的力被分离成归因于声辐射力的空间振荡分量和归因于流体流动的恒定力。当声学装置的驱动条件改变时，振荡力（> 2.5pN（pp））和流动力（
Direct measurement of the forces experienced by micro-spheres in an acoustic standing wave device have been obtained using calibrated optical traps generated with holographic optical tweezers. A micro-sphere, which is optically trapped in three dimensions, can be moved through the acoustic device to measure forces acting upon it. When the micro-sphere is subjected to acoustic forces, it's equilibrium position is displaced to a position where the acoustic forces and optical forces are balanced. Once the optical trapping stiffness has been calibrated, observation of this displacement enables a direct measurement of the forces acting upon the micro-sphere. The measured forces are separated into a spatially oscillating component, attributed to the acoustic radiation force, and a constant force, attributed to fluid streaming. As the drive conditions of the acoustic device were varied, oscillating forces (>2.5 pN(pp)) and streaming forces (