Laser generated ultrasound using directly coated fibre optic patchcords

Abstract

A novel technique is presented for laser generation of ultrasound using low power laser sources and fibre optic patchcords with coated end faces. Absorption of the laser pulse takes place in the coating on the end of the fibre, which in turn generates an ultrasonic stress wave by means of thermoelastic expansion. Results for laser generation of ultrasound in a glass plate are presented, alongside a comparison between ultrasonic generation by coated fibres and direct illumination in aluminium plates.