Courtney, C. R. P., Demore, C., Wu, H., Grinenko, A., Wilcox, P. D., Cochran, S., & Drinkwater, B. W. (2014). Independent trapping and manipulation of microparticles using dexterous acoustic tweezers. Applied Physics Letters, 104(15), 154103. http://doi.org/10.1063/1.4870489
http://scitation.aip.org/content/aip/journal/apl/104/15/10.1063/1.4870489
Abstract
An electronically controlled acoustic tweezer was used to demonstrate two acoustic manipulation phenomena: superposition of Bessel functions to allow independent manipulation of multiple particles and the use of higher-order Bessel functions to trap particles in larger regions than is possible with first-order traps. The acoustic tweezers consist of a circular 64-element ultrasonic array operating at 2.35 MHz which generates ultrasonic pressure fields in a millimeter-scale fluid-filled chamber. The manipulation capabilities were demonstrated experimentally with 45 and 90-μm-diameter polystyrene spheres. These capabilities bring the dexterity of acoustic tweezers substantially closer to that of optical tweezers.
In the news
http://www.labnews.co.uk/news/ultrasonic-hands-grip-microparticles-22-05-2014/
http://www.bath.ac.uk/news/2014/05/14/ultrasonic-hands/
Bruce Drinkwater 