Focusing with two-dimensional angular-symmetric circular acoustic lenses
ACOUSTICAL PHYSICS, vol.57, no.3, pp.292-300, 2011 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 57 Issue: 3
- Publication Date: 2011
- Doi Number: 10.1134/s1063771011030067
- Journal Name: ACOUSTICAL PHYSICS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.292-300
- Inonu University Affiliated: Yes
Abstract
Focusing properties of an acoustic lens based on a modified triangular sonic crystal slab whose columns are aligned on concentric arcs of equal radial distance are investigated. Capability of focusing normally-incident plane waves is demonstrated by means of Finite Element Method. Focusing mechanisms are discussed on the basis of band structures and equifrequency contours considering a model where triangular lattice is elongated along I"K direction. Focusing behavior of the proposed lens is argued to arise from negative refractions at the air-lens interfaces accompanied by index guiding in its interiors. Wavelength-order confinement in the transverse direction is observed. Double focusing is attributed to geometrical effects and contribution of self guiding is discussed. Possibility of occurrence of birefraction at the input face of the lens together with positive refraction at the output face is also discussed.