A non-contact scanning system for laser ultrasonic defect imaging

A non-contact scanning system is described which is capable of producing two-dimensional ultrasonic images of defects in opaque materials. Lasers are used both for generation and detection of ultrasound. Short-duration high-power ( approx 2 MW) laser pulses are used to generate ultrasound on the sur...

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Bibliographic Details
Published inMeasurement science & technology Vol. 2; no. 7; pp. 628 - 634
Main Authors Hoyes, J B, Shan, Q, Dewhurst, R J
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.07.1991
Institute of Physics
Subjects
Acoustics
Exact sciences and technology
Fundamental areas of phenomenology (including applications)
Physics
Ultrasonics, quantum acoustics, and physical effects of sound
Fabry Pérot interferometer
Laser
Wave detection
Wave generation
Experimental study
Acoustic image
Optoacoustic effect
Ultrasound
Scanning device
Defect detection
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Summary:A non-contact scanning system is described which is capable of producing two-dimensional ultrasonic images of defects in opaque materials. Lasers are used both for generation and detection of ultrasound. Short-duration high-power ( approx 2 MW) laser pulses are used to generate ultrasound on the surface of a sample. Such ultrasound in the form of steps or pulses propagates through the sample and, after interaction with defects, are monitored by a 50 cm confocal Fabry--Perot interferometer. The interferometer uses back-scattered laser light from the sample's surface, which can be diffused in nature. System sensitivity is sufficient for applications on optically rough surfaces. Two-dimensional scans have been performed, leading to computer-generated images of artifical defects in Al. Spectra, Graphs. 18 ref.--AA(UK).
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
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ISSN:0957-0233
1361-6501
DOI:10.1088/0957-0233/2/7/009