Acoustic tractor beam

Démoré, C. E. M., Dahl, P. M., Yang, Z., Glynne-Jones, P., Melzer, A., Cochran, S. , MacDonald, M. P. and Spalding, G. C. (2014) Acoustic tractor beam. Physical Review Letters, 112(17), 174302. (doi: 10.1103/PhysRevLett.112.174302) (PMID:24836252)

Abstract

Negative radiation forces act opposite to the direction of propagation, or net momentum, of a beam but have previously been challenging to definitively demonstrate. We report an experimental acoustic tractor beam generated by an ultrasonic array operating on macroscopic targets (gt;1  cm) to demonstrate the negative radiation forces and to map out regimes over which they dominate, which we compare to simulations. The result and the geometrically simple configuration show that the effect is due to nonconservative forces, produced by redirection of a momentum flux from the angled sides of a target and not by conservative forces from a potential energy gradient. Use of a simple acoustic setup provides an easily understood illustration of the negative radiation pressure concept for tractor beams and demonstrates continuous attraction towards the source, against a net momentum flux in the system.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Spalding, Professor Gabriel and Cochran, Professor Sandy
• Authors: Démoré, C. E. M., Dahl, P. M., Yang, Z., Glynne-Jones, P., Melzer, A., Cochran, S., MacDonald, M. P., and Spalding, G. C.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy; College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review Letters
• Publisher: American Physical Society
• ISSN: 0031-9007
• ISSN (Online): 1079-7114