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.
展开▼
