Observation of diffraction-free propagation of surface acoustic waves around a homogeneous isotropic solid sphere

Yusuke Tsukahara, Noritaka Nakaso, Hideo Cho, Kazushi Yamanaka

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

This letter shows an unexpected phenomenon where a surface acoustic wave (Rayleigh wave) excited by a line source with a finite length on a solid sphere propagates along the great circle in a direction perpendicular to the line source without beam spreading due to diffraction. In experiments, a piezoelectric transducer, 1.5 mm in width and 20 mm in length, was glued on a surface of a glass ball, 80 mm in diameter, as a line source with a finite length. A beam of Rayleigh waves with frequencies centered at 1.1 MHz was excited in either direction perpendicular to the transducer length. A receiving transducer with a circular aperture, 2 mm in diameter, was used in direct contact with the surface to detect the distribution of vibration over the surface of the ball. It was observed that the excited Rayleigh wave propagated along a great circle of the ball for at least four roundtrips. The beam was confined within a narrow path around the ball, the width of which was no more than 20 mm.

Original languageEnglish
Pages (from-to)2926-2928
Number of pages3
JournalApplied Physics Letters
Volume77
Issue number18
DOIs
Publication statusPublished - 2000 Oct 30

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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