Laser Ultrasonic Thermoelastic/Ablation Generation with Laser Interferometric Detection in Graphite/Polymer Composites

Thermoelastic/Ablatic Laser Generated Ultrasound in Graphite/Polymer Composites Detected with a Cfp-Based System in Reflection Configuration

“…However, a preliminary experiment suggests an explanation of the inconsistent AB amplitudes observed in repeated measurements in previous work [3]. The new measurements indicate that this may be due to the dependence of the mixture of TE and AB components on the detection site.…”

“…To minimize any stray signal from the generation beam a blue-green optical filter was placed in front of the detector, and the detector was oriented to collect light arriving perpendicular to the beam. The method of optical detection demonstrated here for generation in the infrared, and previously [3] for generation with visible Iaser radiation, could also be used in an industrial setting to monitor (and avoid) undesired ablation during laser-based ultrasonic testing.…”

“…The Doppler-shifted light scattered from the sample is collected by a series of optical components which direct the light into the CFP. Previously [3] the CFP was operated in a transmission mode, z. e. the ultrasonic signal was derived from light transmitted through the CFP. In the current configuration the ultrasonic output is obtained by collecting the light refiected by the CFP etalon.…”