Journal of Nondestructive Evaluation

, Volume 12, Issue 3, pp 187–192 | Cite as

Pulsed laser energy through fiberoptics for generation of ultrasound

  • Nancy M. Carlson
  • John A. Johnson


Laser pulses are an effective, noncontacting technique for generating ultrasound in materials. However, for this approach to be practical, a versatile and safe method of delivering the laser pulses must be developed that eliminates exposed beams steered by mirrors and focused by lenses. Investigations by several researchers using fiberoptic delivery systems indicate that fiberoptics may be a viable method for the delivery of laser energy to generate acoustic energy. The main problem experienced with the fiberoptic delivery systems has been the inability to deliver high-energy, short-duration pulses via a fiber for thousands of pulses with no fiber damage and with constant energy output. This paper presents a technique for laser generation of sound using fiberoptics that continuously delivers sustained 20 ns pulses at a pulsing rate of 30 Hz from a doubled, Q-switched Nd:YAG laser operating at 532 nm with output energy from the fiber-optic system up to 26 mJ/pulse. The delivery system is used to excite ultrasound in a molten weld pool as part of a research effort to develop a noncontacting sensing system for real-time weld inspection.

Key words

Fiberoptics ultrasound laser generation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    G. V. Garcia, N. M. Carlson, K. L. Telschow, and J. A. Johnson, “Noncontacting Laser Ultrasonic Generation and Detection at the Surface of a Molten Metal,”Review of Progress in QNDE 9, Plenum Press, pp. 1981–1990, 1990.Google Scholar
  2. 2.
    J. A. Johnson and N. M. Carlson. Noncontact ultrasonic sensing of weld pools for automated welding, inProceedings of the 3rd International Symposium on the Nondestructive Characterization of Materials. Saarbrucken, West Germany, October 3–6, 1988.Google Scholar
  3. 3.
    D. A. Hutchins and A. C. Tam. Pulsed photoacoustic materials characterization,IEEE Trans. Ultrasonics, Ferroelectrics, Frequency Control UFFC-vn33 (5):429–449 (1986).Google Scholar
  4. 4.
    C. P. Burgeret al. Laser excitation through fiber optics for NDE,J. Nondestr. Eval. 7(1):57–64 (1987).Google Scholar
  5. 5.
    R. J. Dewhurst, A. G. Nurse, and S. B. Palmer. High power optical fibre delivery system for the generation of ultrasound.Ultrasonics 26:307–310 (1988).Google Scholar
  6. 6.
    A. J. A. Bruinsma and J. A. Vogel. Ultrasonic noncontact inspection system with optical fiber methods.Appl. Opt. 27 (22):4690–4695 (1988).Google Scholar
  7. 7.
    Y. H. Berthelot and J. Jarzynski, “Directional Laser Generation and Detection of Ultrasound with Arrays of Optical Fibers,”Review of Progress in QNDE 9, pp. 463–470, 1990.Google Scholar
  8. 8.
    Input coupler is key to laser fiber-optic welding system.Res. Develop. 24 (October 1988).Google Scholar
  9. 9.
    J. A. Smith, Idaho National Engineering Laboratory, Idaho Falls, ID, Private Communication, January 1989.Google Scholar
  10. 10.
    S. W. Allison, G. T. Gilles, D. W. Magnuson, and T. S. Pagano. Pulsed laser damage to optical fibers,Appl. Opt. 24(19):3140–3144 (1985).Google Scholar
  11. 11.
    B. J. Skutnik, W. B. Beck, and M. H. Hodge. Hazards for fiber optics in the medical application environment. Proceedings of SPIE 787, Optical Techniques for Sensing and Measurement in Hostile Environments, Orlando Florida, May 21–22, 1987, pp. 8–16.Google Scholar
  12. 12.
    Gregory Burke, General Fiber Optics, Cedar Grove, New Jersey, Private communication, June 1989.Google Scholar
  13. 13.
    ANSI Standard Z136.1-1986 for the Safe Use of Lasers (American National Standards Institutes, New York, 1986), Table 5, p. 34.Google Scholar
  14. 14.
    J. A. Johnson and N. M. Carlson. Weld energy reduction by using concurrent nondestructive evaluation.NDT Int. 19:190–196 (June 1986).Google Scholar
  15. 15.
    J. B. Walter, K. L. Telschow, G. V. Garcia, and D. C. Kunerth, “Process Monitoring Using Optical Ultrasonic Wave Detection,”Review of Progress in QNDE 9, Plenum Press, pp. 2063–2069, 1990.Google Scholar
  16. 16.
    D. C. Kunerth, K. L. Telschow, and J. B. Walter. Characterization of porosity distributions in advanced ceramics: A comparison of ultrasonic methods.Mater. Eval. 47:571–575 (May 1989).Google Scholar

Copyright information

© Plenum Publishing Corporation 1993

Authors and Affiliations

  • Nancy M. Carlson
    • 1
  • John A. Johnson
    • 1
  1. 1.Idaho National Engineering LaboratoryIdaho Falls

Personalised recommendations