Location

La Jolla, CA

Start Date

1-1-1993 12:00 PM

Description

Laser ultrasonics has been the focus of several research efforts over the last two decades. The main advantage of the technique is its noncontact nature which alleviates the problem of sensor coupling inherent in conventional techniques. However, laser ultrasonics has some limitations When operated in the thermoelastic regime, where no damage is inflicted on the surface of the specimen, the signal-to-noise ratio (SNR) is very small, particularly when compared with conventional piezoelectric generation.[1] Several authors have proposed increasing the SNR by producing a source with spatial periodicity designed to enhance a particular wavelength. Royer and Dieulasaint [2] have used a periodic mask, Wagner et al [3] have used a lenticular array, Vogel [4] and Berthelot and Jarzynski [5] have used an array of optical fibers. Cielo et al. [6] increased the SNR by increasing the displacement by geometrical focusing. They detected the displacement of surface waves at the center of an anular source and demonstrated that it was 20 times greater than that of a spot source.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12A

Chapter

Chapter 2: Emerging Inspection Technologies

Section

Laser-Based Ultrasonics

Pages

579-586

DOI

10.1007/978-1-4615-2848-7_73

Language

en

File Format

application/pdf

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Jan 1st, 12:00 PM

Laser generation of Rayleigh and Lamb waves for ultrasonic nondestructive testing

La Jolla, CA

Laser ultrasonics has been the focus of several research efforts over the last two decades. The main advantage of the technique is its noncontact nature which alleviates the problem of sensor coupling inherent in conventional techniques. However, laser ultrasonics has some limitations When operated in the thermoelastic regime, where no damage is inflicted on the surface of the specimen, the signal-to-noise ratio (SNR) is very small, particularly when compared with conventional piezoelectric generation.[1] Several authors have proposed increasing the SNR by producing a source with spatial periodicity designed to enhance a particular wavelength. Royer and Dieulasaint [2] have used a periodic mask, Wagner et al [3] have used a lenticular array, Vogel [4] and Berthelot and Jarzynski [5] have used an array of optical fibers. Cielo et al. [6] increased the SNR by increasing the displacement by geometrical focusing. They detected the displacement of surface waves at the center of an anular source and demonstrated that it was 20 times greater than that of a spot source.