Photoacoustic generation: all-optical fibre transducers

Abstract

Innovative photoacoustic transducers for ultrasonic NDE, smart structure, and clinical diagnosis are proposed. The working principle is based on thermal conversion of laser pulses into a metallic film evaporated directly onto the tip of an optical fibre, or, alternatively, on the extrados of an uncladded and U-bent fibre. Unique features of the proposed transducers are: very high miniaturization and potential easy embedding in smart structure. Additional advantages are: good conversion efficiency, high acoustic power in high frequency range, large bandwidth, and spectral purity of the ultrasonic signal.