Ultra-Fast Acoustofluidic Particle Focusing Using Lateral Modes of a Plate Transducer

To the best of our knowledge, we are the first group to explicitly use lateral modes of an acoustic plate transducer for the focusing of particles in fluidic channels yielding high performance in numerical simulations as well as in experiments. The developed experimental setup allows rapid chip mounting via a custom chip holder featuring integrated fluid connection and transducer support. Low heat generation of the lateral modes allows for high actuation voltages. Our best result, particle focusing in 25 milliseconds in a 1240 micrometer wide channel, corresponds to an acoustic energy density of about 2000 J/m
³
, which exceeds the highest value reported in literature. Further simulations show promising scalability, demonstrating that smaller and integrated devices using lateral modes could be tackled using this approach for sub-micrometer particle handling through the higher frequencies and thus shorter wavelengths of the acoustic wave inside the channel.