Acoustic and flexural excitation of a floating structure by a single laser pulse

The acoustic and flexural vibrations of a small-scale floating structure following irradiation by a pulsed Nd:glass laser are compared with a radiated underwater sound field. A single subablative laser pulse of 600-μs duration was used both to bend and shock the floating structure at the irradiation site. The laser pulse caused the structure to flex at a frequency of approximately 1 kHz whereas relaxation oscillations in the laser output simultaneously excited ultrasonic Lamb waves within the material bulk. We present results to illustrate the broad bandwidth provided by this unusual form of excitation.