Microparticle trapping in an ultrasonic Bessel beam

Area of Science:

• Acoustic manipulation
• Microparticle trapping
• Photonics and acoustics

Background:

• Acoustic tweezers offer non-contact manipulation of microparticles.
• Traditional acoustic traps often require complex setups.
• The development of novel acoustic lens designs is crucial for advancing manipulation capabilities.

Purpose of the Study:

• To design and fabricate a novel acoustic trap utilizing a multi-foci Fresnel lens.
• To investigate the generation of an acoustic Bessel beam for microparticle manipulation.
• To demonstrate the capability of trapping microparticles using negative axial radiation force.

Main Methods:

• Fabrication of a multi-foci Fresnel lens on a lead zirconate titanate sheet.
• Design of the lens to mimic Axicon lens functionality for Bessel beam generation.
• Experimental trapping of lipid particles and microspheres using the acoustic tweezers.

Main Results:

• The multi-foci Fresnel lens successfully generated an acoustic Bessel beam.
• The acoustic trap exhibited negative axial radiation force, enabling particle trapping.
• Lipid particles (50-200 μm) and microspheres (70-90 μm) were trapped at distances of 2-5 mm.

Conclusions:

• A novel acoustic trap based on a multi-foci Fresnel lens is demonstrated.
• The device enables non-contact trapping of microparticles via an acoustic Bessel beam.
• This technology holds potential for applications in microparticle manipulation and handling.