English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report Bessel-like beam formation of acoustic waves by means of anaxisymmetric grating of rigid tori. The results show that the generated beampattern is similar to that of Bessel beams, characterized by elongatednon-diffracting focal spots. A multiple foci structure is observed, due to thefinite size of the lens. The dependence of the focal distance on the frequencyis also discussed, on the basis of an extended grating theory. Experimentalvalidation of acoustic Bessel-like beam formation is also reported for soundwaves. The results can be generalized to wave beams of different nature, asoptical or matter waves.

Acoustic Bessel-like beam formation by an axisymmetric grating