Experimental observation of locally-resonant and Bragg band gaps for surface guided waves in a phononic crystal of pillars

Younes Achaoui*, Abdelkrim Khelif, Sarah Benchabane, Laurent Robert, Vincent Laude

*Corresponding author for this work

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238 Citations (Scopus)

Abstract

We report on the experimental study of the propagation of surface guided waves in a periodic arrangement of pillars on a semi-infinite medium. Samples composed of nickel pillars grown on a lithium niobate substrate were prepared and wide bandwidth transducers were used for the electrical generation of surface elastic waves. We identify a complete band gap for surface guided waves appearing at frequencies markedly lower than the Bragg band gap. Using optical measurements of the surface vibrations and by comparison with a finite element model, we argue that the low frequency band gap arises because of local resonances in the pillars. When resonance is reached, the acoustic energy is confined inside the pillars and transmission through the array is strongly reduced. At higher frequencies and inside the Bragg band gap, the incident surface elastic waves are almost completely reflected and the observed exponential decay of the transmission is similar to the case of phononic crystals made of holes in a substrate.

Original languageEnglish
Article number104201
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume83
Issue number10
DOIs
Publication statusPublished - 14 Mar 2011
Externally publishedYes

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