Title :
Wave focsuing in phononic thin plates
Author :
Tsung-Tsong Wu ; Chun-Wei Chen
Author_Institution :
Inst. of Appl. Mech., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
This paper aims at investigating the focusing of the lowest anti-symmetric Lamb wave (A0 mode) in both the GRIN and negative refraction (NR) based PC thin plates. Numerical results demonstrated that Lamb wave can be compressed efficiently in the GRIN PC plate and forms a focusing region along the centre line of the GRIN PC. The amplitude at the focusing region can be doubled approximately, while the bandwidth can be as large as 33%. For the case of the flat PC lens in a thin plate, numerical results showed the existence of the NR-based focusing which is similar to that of the bulk wave case. Simulation results showed that the full widths at half maximum (FWHM) of the focal spots of both the GRIN PC plate and the flat PC lens are around the order of one wavelength.
Keywords :
gradient index optics; lenses; metamaterials; phononic crystals; surface acoustic waves; GRIN phononic thin plate; flat phononic lens; focal spots; focusing region; lowest antisymmetric Lamb wave focusing; negative refraction based phononic thin plate; negative refraction-based focusing; Acoustic waves; Aluminum; Focusing; Lattices; Lenses; Numerical simulation; Sun;
Conference_Titel :
Ultrasonics Symposium (IUS), 2012 IEEE International
Conference_Location :
Dresden
Print_ISBN :
978-1-4673-4561-3
DOI :
10.1109/ULTSYM.2012.0286
