Laser-Ultrasonics: A new tool for the industry

摘要

Laser-ultrasonics is an advanced ultrasonic technique based on the generation and detection of ultrasound with lasers. In this paper we present recent developments performed at the Industrial Materials Institute of the National Research Council of Canada, which includes progress made in the basic technology and in applications. We discuss the recent developments on the use of photorefractive crystals in self-adapted interferometers for the detection of ultrasound and compare the performance obtained with the more establsihed confocal Fabry-Perot demodulator. We present an appraoch based on the Synthetic Aperture Focusing Technique for enhancing the detection f small defects. Several applications that have reached various degrees of maturity are outlined, including the inspection of polymer-matrix composites, and detection of corrosion in the lap joints of aging aircraft, the characterization of the microstructure of steel and the monitoring of its evolution with temperature, the determination of the in-plane stiffness and the applied tension of a paper web.