Scaling acoustic vortex traps with topological charge.

Area of Science:

• Acoustic manipulation
• Particle trapping
• Vortex beams

Background:

• Three-dimensional acoustic vortex trapping of Mie particles is established.
• Previous research explored vortex beam properties but lacked detailed analysis of topological charge effects on trapping.

Purpose of the Study:

• To analytically, numerically, and experimentally investigate how a focused vortex's topological charge influences particle trap size, stability, and position.
• To establish design principles for acoustic trapping applications.

Main Methods:

• Utilized a plane wave transducer with a phase-modifying metalens to generate focused vortex beams.
• Performed analytical, numerical, and experimental analyses.
• Experimentally validated findings using a piezoelectric transducer and silicone lens to trap polymer particles.

Main Results:

• Demonstrated a strong linear dependence of trap size on the topological charge.
• Confirmed that increasing topological charge shifts the trap position closer to the acoustic source.
• Experimentally trapped polymer particles of various sizes.

Conclusions:

• Topological charge is a key parameter for controlling acoustic trap dimensions and position.
• Findings provide essential design principles for biomedical and particle manipulation technologies using acoustic trapping.