Comment on "Theory of tailoring sonic devices: Diffraction dominates over refraction"

TL;DR

This paper critiques a previous study on acoustic device focusing, reexamining calculations and clarifying that refraction, not diffraction, is the dominant mechanism in observed effects.

Contribution

It provides a critical reanalysis of prior theoretical interpretations, emphasizing the role of refraction over diffraction in acoustic focusing.

Findings

Refraction plays a significant role in acoustic focusing.

Some previous interpretations of experimental results are misleading.

Theoretical calculations are reexamined to clarify mechanisms.

Abstract

Recently N. Garcia et al. (Phys. Rev. E 67, 046606 (2003)) theoretically studied several acoustic devices with dimensions on de order of several wavelenghts. The authors discussed on experimental results previously reported by several of us (F. Cervera et al., Phys. Rev. Lett. 88, 023902 (2002)). They concluded that diffraction and not refraction is the ominating mechanism that explain the focusing effects observed in those experiments. In this Comment we reexamined their calculations and discussed why some of their interpretations of our results are misleading.