Demonstration of self-healing and scattering resilience of acoustic Bessel beams

In optics, Bessel beams have seen extensive use because they exhibit a non-diffracting propagation and a self-reconstruction capability beyond obstacles encountered along their path, with an ensuing pronounced resilience to scattering. Whether such peculiarities, characteristic of the Helmholtz equation for transverse E and B fields, are manifested by longitudinal acoustic fields is currently unknown. Here, we report the experimental demonstration of the self-healing and the scattering resilience properties of a non-diffracting zero-order acoustic Bessel beam. The beam is obtained interfering ultrasound waves with a propagating vector lying on a cone and is found to be capable of self-reconstructing beyond large spherical obstacles and multiple scattering layers.