Acoustic Tweezers Based on Linear Fresnel Lens with Air Cavities for Large Volume Particle Trapping

This paper reports a novel acoustic tweezers with multi-foci linear Fresnel lens that was designed to create a large Bessel beam zone for contactless, non-invasive object trapping in liquid. The tweezers was built on a 1-mm-thick lead zirconate titanate (PZT) substrate with rectangular air-cavity Fresnel lens having multiple focal lengths. With 25 V
_pp
continuous 2.32 MHz sinusoidal drive, the acoustic tweezers is capable of trapping a silicon chip of 5.30×0.67×0.51 mm
³
in size and 3.98 mg in mass along with two 500-μm-diameter Polyethylene microspheres.