title: NDT of fiber-reinforced composites with a new fiber-optic pump-probe laser-ultrasound system.
abstract: Laser-ultrasonics is an attractive and powerful tool for the non-destructive testing and evaluation (NDT&E) of composite materials. Current systems for non-contact detection of ultrasound have relatively low sensitivity compared to contact peizotransducers. They are also expensive, difficult to adjust, and strongly influenced by environmental noise. Moreover, laser-ultrasound (LU) systems typically launch only about 50 firings per second, much slower than the kHz level pulse repetition rate of conventional systems. As demonstrated here, most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive, high repetition rate nanosecond fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe beam detector. In particular, a modified fiber-optic balanced Sagnac interferometer is presented as part of a LU pump-probe system for NDT&E of aircraft composites. The performance of the all-optical system is demonstrated for a number of composite samples with different types and locations of inclusions.
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA, USA ; International Laser Center, Moscow State University, Moscow, Russian Federation.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pelivanov
authors.affiliation: Union College, Schenectady, NY, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Buma
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA, USA.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Xia
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA, USA.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Wei
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
keywords: Composite materials; Fiber-optic pump–probe system; Laser ultrasound; NDT&E; Optoacoustics; Photoacoustics