Acoustic Lock: Position and orientation trapping of non-spherical sub-wavelength particles in mid-air using a single-axis acoustic levitator

L. Cox*, A. Croxford, B. W. Drinkwater, A. Marzo

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

22 Citations (Scopus)
567 Downloads (Pure)

Abstract

We demonstrate acoustic trapping in both position and orientation of a non-spherical particle of sub-wavelength size in mid-air. To do so, we multiplex in time a pseudo-one-dimensional vertical standing wave and a twin-trap; the vertical standing wave provides converging forces that trap in position, whereas the twin-trap applies a stabilising torque that locks the orientation. The device operates at 40 kHz, and the employed multiplexing ratio of the 2 acoustic fields is 100:50 (standing:twin) periods. This ratio can be changed to provide tunability of the relative trapping strength and converging torque. The torsional spring stiffness of the trap is measured through simulations and experiments with good agreement. Cubes from λ/5.56 (1.5 mm) to λ/2.5 (3.4 mm) side length were stably locked. We also apply this technique to lock different non-spherical particles in mid-air: cubes, pyramids, cylinders, and insects such as flies and crickets. This technique adds significant functionality to mid-air acoustic levitation and will enable applications in micro-scale manufacturing as well as containment of specimens for examination and 3D-scanning.

Original languageEnglish
Article number054101
Number of pages6
JournalApplied Physics Letters
Volume113
Issue number5
Early online date31 Jul 2018
DOIs
Publication statusPublished - 31 Jul 2018

Fingerprint Dive into the research topics of 'Acoustic Lock: Position and orientation trapping of non-spherical sub-wavelength particles in mid-air using a single-axis acoustic levitator'. Together they form a unique fingerprint.

Cite this