Abstract
We present acoustic drill beams, a novel structured sound beam exhibits a dynamic intensity distribution matching the shape of a helix. The intensity distribution rotates along the beam axis with controlled direction and angular frequency, resembling in this way the shape of a mechanical drill bit. Acoustic drill beams emerge as the spatiotemporal interference of two confocal, detuned vortex beams. The beam parameters are fully tuneable. The detuned frequency, the detuned wavenumber and the detuned topological charge of the composing beams control the number of drill arms, the winding period, the rotational speed, and their direction. We show that elongated drill beams are obtained using two high-order Bessel beams, allowing analytical solutions for optimal overlap. In addition, drill beams can also be synthesised using focused ultrasound vortices. Analytical, numerical, and experimental results are shown in the ultrasound regime using a lowcost device based on two 1 MHz confocal piezoelectric transducers and 3D printed acoustic holograms. This new wave structure opens new avenues for wave-matter interaction, such as contactless particle manipulation, matter processing or biomedical applications.
BibTeX citation
@inproceedings{JimenezTEC2022a,
author = {Noé Jiménez and Enrique M. González-Mateo and Francisco Camarena and Kestutis Staliunas},
booktitle = {Tecniacústica 2022: 53º Congreso Español de Acústica. XII Congreso Ibérico de Acústica. European Symposium on NVH in Electric Vehicles. Elche, Spain. 2-4 November},
doi = {http://www.sea-acustica.es/fileadmin/Elche22/ID-70.pdf},
editor = {Conference proceedings},
month = {11},
organization = {Sociedad Española de Acústica},
pages = {1141-1144},
series = {Oral},
title = {Acoustic drill beams: twisting wave intensity by the superposition of detuned vortices},
url = {http://www.sea-acustica.es/fileadmin/Elche22/ID-70.pdf},
year = {2022}
}