Far-field focusing of acoustic waves by a two-dimensional phononic crystal with surface gratingZhaojian He1, Xiaochun Li2, Ke Deng1, Jun Mei1 and Zhengyou Liu1
1 Key Lab of Acoustic and Photonic Materials and Devices of Ministry of Education and Department of Physics, Wuhan University - Wuhan 430072, China
2 Department of Physics, Center South University - Changsha 410073, China
received 16 May 2009; accepted in final form 18 August 2009; published September 2009
published online 16 September 2009
We show that by adding a surface grating onto a two-dimensional phononic crystal slab, negative refraction of acoustic waves can be observed in the originally forbidden frequency region. Far-field focusing by this mechanism is demonstrated with exact numerical simulations, which is in agreement with the physical analysis based on the wave-beam negative-refraction law. Potential applications of the effect in acoustic devices are expected.
78.20.Ci - Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity).
43.20.+g - General linear acoustics.
43.58.+z - Acoustical measurements and instrumentation.
© EPLA 2009