Quasi-Bessel surface acoustic wave for dynamic acoustic manipulation

Abstract

Acoustic manipulation using surface acoustic wave has aroused widespread interest in life sciences, biomedical, and bioanalytical chemistry. Acoustic manipulation for different applications requires different acoustic fields. Bessel beams are non-diffractive and re-constructable, bringing possibility and versatility of acoustic manipulation integrated on microfluidic chips. To date, there are a few studies on constructing Bessel surface acoustic waves. Moreover, there is still a lack of dynamic acoustic manipulation using Bessel surface acoustic waves propagating along a surface of piezoelectric substrate with simple and high-precision devices. Here, we design a device with two omnidirectional equifrequency interdigital transducers to form a quasi-Bessel surface acoustic wave by means of coherent interference. The proposed device avoids influences of anisotropy on its operating frequency, making its quasi-Bessel beam accurately and stably conform to the predetermined design acoustic field. This acoustic field could control micrometer to submicrometer particles and dynamically move particles along lateral direction and axial direction of the propagation of quasi-Bessel beam. A phenomenon similar to negative force appeared when the two-micron spherical particles were manipulated. The quasi-Bessel beam formed by our device can provide a versatile movement for on-chip acoustic manipulation.