Acoustic tweezers via sub-time-of-flight regime surface acoustic waves.
Acoustic tweezers via sub-time-of-flight regime surface acoustic waves.
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DOI：
10.1126/sciadv.1600089
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发表时间：
2016-07
期刊：
影响因子：
13.6
通讯作者：
Ai Y
中科院分区：
文献类型：
--
作者：
Collins DJ;Devendran C;Ma Z;Ng JW;Neild A;Ai Y
研究人员使用脉冲激励来产生局部2D声学镊子，用于空间选择性微流体图案化。微米级声波对于精细的光学机械和声流体操纵是非常有用的，其中这些场在空间上沿着换能器孔径沿着而不是沿着声学传播方向局部化。在声学镊子的情况下，这种常规的声学驻波导致颗粒和细胞在微流体通道的整个宽度上图案化，从而防止选择性捕获。我们演示了使用纳秒级脉冲表面声波（SAW）的脉冲周期小于相对换能器之间的飞行时间，以产生本地化的时间平均图案化区域，同时使用传统的电极结构。通过施加脉冲延迟、频率调制和相移，这些波节位置可以容易且任意地在二维中定位并且定位在图案化区域本身内。这种简单的概念增加了新的空间维度，声场可以以类似于光镊的方式在SAW应用中被定位到该空间维度，包括空间选择性声镊和光波导。
Researchers use pulsed excitation to generate localized 2D acoustic tweezers for spatially selective microfluidic patterning. Micrometer-scale acoustic waves are highly useful for refined optomechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning across the entire width of a microfluidic channel, preventing selective trapping. We demonstrate the use of nanosecond-scale pulsed surface acoustic waves (SAWs) with a pulse period that is less than the time of flight between opposing transducers to generate localized time-averaged patterning regions while using conventional electrode structures. These nodal positions can be readily and arbitrarily positioned in two dimensions and within the patterning region itself through the imposition of pulse delays, frequency modulation, and phase shifts. This straightforward concept adds new spatial dimensions to which acoustic fields can be localized in SAW applications in a manner analogous to optical tweezers, including spatially selective acoustic tweezers and optical waveguides.