Cleary, A. and Veres, Istvan and Thursby, G.J. and McKee, C. and Armstrong, I. and Pierce, S.G. and Culshaw, B. (2010) Low power laser generated ultrasound : signal processing for time domain data acquisition. In: Laser Ultrasonics 2010, 2010-07-05 - 2010-07-08, Bordeaux, France.
The use of low power modulated laser diode systems has previously been established as a suitable method for non-destructive laser generation of ultrasound. Using a quasi-continuous optical excitation amplified by an erbium-doped fibre amplifier (EDFA) allows flexible generation of ultrasonic waves, offering control of further parameters such as the frequency content or signal shape. In addition, pseudo-random binary sequences (PRBS) can be used to improve the detected impulse response. Here we compare two sequences, the m-sequence and the Golay code, and discuss the advantages and practical limits of their application with laser diode based optical excitation of ultrasound.
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