Differential fibre-optic sensing of laser-generated ultrasound

Author

Williams, B.A. ; Dewhurst, R.J.

Author_Institution

Dept. of Instrum. & Anal. Sci., Univ. of Manchester Inst. of Sci. & Technol., UK

Volume

31

Issue

5

fYear

1995

fDate

3/2/1995 12:00:00 AM

Firstpage

391

Lastpage

392

Abstract

A differential fibre-optic device has been developed for noncontact detection of laser-generated ultrasound. Using a 5 mW He-Ne laser as the source, laser beam delivery on to the sample of the surface utilised a singlemode fibre and lens combination. When photoacoustic ultrasonic transients propagated across the surface, the incident spot was perturbed. With backscattered light monitored by a fibre-optic bundle incorporating differential photodetection. Symmetric and asymmetric Lamb wave modes have been observed in a 50 μm aluminium sheet, as have longitudinal and Rayleigh waves in a 30 mm-thick sample

Keywords

Rayleigh waves; fibre optic sensors; laser beam applications; photoacoustic effect; photodetectors; surface acoustic waves; ultrasonic materials testing; 30 micron; 5 mW; 50 micron; Al; Al sheet; He-Ne; NDT; Rayleigh waves; US applications; asymmetric Lamb wave modes; backscattered light monitor; differential fibre-optic sensing; differential photodetection; fibre-optic bundle; laser-generated ultrasound; longitudinal waves; noncontact detection; photoacoustic ultrasonic transients; single-mode fibre; singlemode fibre/lens combination; symmetric Lamb wave modes;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19950235

Filename

369997