title: Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves.
abstract: All-optical monitoring of the nonlinear motion of a  surface-breaking crack is reported. Crack closing is induced by  quasi-continuous laser heating, while Rayleigh surface acoustic pulses and bulk longitudinal surface skimming acoustic pulses are also generated and detected by lasers. By exploiting the strong dependence of the acoustic pulses reflection and transmission efficiency on the state-open or closed-of the contacts between the crack faces, the parametric modulation of ultrasonic pulses is achieved. It is observed that bulk acoustic waves skimming along the surface can be more sensitive to crack motion than Rayleigh surface waves.
authors.affiliation: LAUM, UMR-CNRS 6613, Université du Maine, Avenue O. Messiaen, 72085 Le Mans, France. Chenyin.Ni@univ-lemans.fr
authors.forename: Chen-Yin
authors.initials: CY
authors.lastname: Ni
authors.forename: Nikolay
authors.initials: N
authors.lastname: Chigarev
authors.forename: Vincent
authors.initials: V
authors.lastname: Tournat
authors.forename: Nicolas
authors.initials: N
authors.lastname: Delorme
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Shen
authors.forename: Vitalyi E
authors.initials: VE
authors.lastname: Gusev