Title :
Acoustic reflectivity enhancement using higher-order nonlinear reflection mode
Author :
Maev, Roman G. ; Solodov, Igor Yu.
Author_Institution :
Dept. of Phys., Windsor Univ., Ont., Canada
Abstract :
Acoustic wave reflection is studied for sharp nonlinear inhomogeneities embedded into nonlinear medium with similar linear characteristics. The higher-order nonlinear reflection mode is used to increase the reflectivity of such inclusions “invisible” in a linearly reflected field. For YZ-LiNbO3 the discontinuity in nonlinear properties was measured to be the most dramatic for the SAW third harmonic generated in the area of the contact acoustic nonlinearity (simulating a closed crack) and acousto-electronic nonlinearity (piezoelectric-semiconductor structure). The experiments revealed from 3 to 4 orders of magnitude increase in reflectivity of the nonlinear inhomogeneities for the third-order nonlinear reflection mode
Keywords :
harmonic generation; inhomogeneous media; lithium compounds; nonlinear acoustics; surface acoustic waves; ultrasonic materials testing; ultrasonic reflection; LiNbO3; SAW third harmonic generation; YZ-LiNbO3; acoustic NDE; acoustic reflectivity enhancement; acousto-electronic nonlinearity; backward harmonics; closed crack simulation; contact acoustic nonlinearity; discontinuity in nonlinear properties; higher-order nonlinear reflection mode; invisible inclusions; nonlinear acoustic imaging; nonlinear medium; piezoelectric-semiconductor structure; sharp nonlinear inhomogeneities; similar linear characteristics; third-order nonlinear reflection mode; Acoustic materials; Acoustic measurements; Acoustic propagation; Acoustic reflection; Acoustic waves; Frequency conversion; Laboratories; Nonlinear acoustics; Physics; Reflectivity;
Conference_Titel :
Ultrasonics Symposium, 1998. Proceedings., 1998 IEEE
Conference_Location :
Sendai
Print_ISBN :
0-7803-4095-7
DOI :
10.1109/ULTSYM.1998.762246
