Low peak-power laser ultrasonics

Stephen Pierce, Alison Cleary, Istvan Veres, Brian Culshaw, Graham Thursby, Campbell Mckee, C. Swift, Ian Armstrong

Research output: Contribution to journalSpecial issue

4 Citations (Scopus)

Abstract

Techniques for the successful excitation of guided ultrasonic waves using a low peak-power laser ultrasonic source are discussed and compared with more conventional Q-switched laser sources. The paper considers acoustic propagation in thin plates, in which the frequencies used, typically only the fundamental guided wave modes, are considered. Aspects of excitation and detection geometry are considered along with the physical mechanisms of photo-acoustic generation and the practical issues surrounding available source wavelengths and power outputs. Understanding of the effects of these constraints is critical for the successful application of the technique. Continuous wave excitation and fully arbitrary modulation schemes are compared, and a technique to control the bandwidth of Golay code modulation is introduced. It is shown that earlier work by the authors was capable of guided wave detection at peak-power densities of 104 W cm− 2. Later work has focussed on the use of erbium-doped fibre amplifiers combined with Golay code modulation to improve the recovered signal-to-noise ratio. Two key applications of the techniques are considered: material properties measurements (using inversion of dispersion curve data) and acoustic emission system calibration.
Original languageEnglish
Pages (from-to)281-301
Number of pages21
JournalNondestructive Testing and Evaluation
Volume26
Issue number3-4
Early online date13 Jul 2011
DOIs
Publication statusPublished - 2011

Keywords

  • ultrasonics
  • lasers
  • laser ultrasonics
  • ultrasonic waves

Fingerprint Dive into the research topics of 'Low peak-power laser ultrasonics'. Together they form a unique fingerprint.

Cite this