The laser generation d ultrasound in solids is reviewed with particular emphasis on the application of this unique ultrasonic source. Three regimes for the generation of ultrasound in solids using lasers in the visible near infrared wavelength region exist: thermoelastic, plasma and constrained surface source regimes. The mechanism for ultrasonic generation in each of these regimes is given. Recent experimental investigations into laser-generated unrasound are also described, including a description d a different mechanism for the generation of ultrasound in solids using a COn laser. Finally, the many applications of lasergenerated ultrasound are reviewed. These applications range from nondestructive testing to the determination of candle flame parameters. Possible future applications are also outlined.

The authors have demonstrated that air breakdown produced just above a metal surface by a pulsed CO2 TEA laser, is an efficient source of ultrasound within the metal. The normal force source produces both longitudinal and shear waves in the bulk and Rayleigh surface waves. No damage is produced on the metal surface. Electromagnetic acoustic transducers provide complementary noncontacting detectors.

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