title: Acoustic resonators for far-field control of sound on a subwavelength scale.
abstract: We prove experimentally that broadband sounds can be controlled and focused at will on a subwavelength scale by using acoustic resonators. We demonstrate our approach in the audible range with soda cans, that is, Helmholtz resonators, and commercial computer speakers. We show that diffraction-limited sound fields convert efficiently into subdiffraction modes in the collection of cans that can be controlled coherently in order to obtain focal spots as thin as 1/25 of a wavelength in air. We establish that subwavelength acoustic pressure spots are responsible for a strong enhancement of the acoustic displacement at focus, which permits us to conclude with a visual experiment exemplifying the interest of our concept for subwavelength sensors and actuators.
authors: Institut Langevin, ESPCI ParisTech, France.
authors: Fabrice
authors: F
authors: Lemoult
authors: Mathias
authors: M
authors: Fink
authors: Geoffroy
authors: G
authors: Lerosey