Selective Manipulation of Microscopic Particles with Precursor Swirling Rayleigh Waves

For contactless manipulation of microparticles, acoustic tweezers offer trapping forces five orders of magnitude greater than their optical counterparts. Establishing a general relation between electrode shape and the resulting acoustic field, the authors present selective, flat tweezers based on acoustic vortices generated by spiral electrodes, the shape of which encodes the phase of the field like a hologram. These devices can be fabricated via standard photolithography, enabling massive production of miniaturized, easily integrable systems for lab-on-a-chip applications.