We report on a laser
ultrasonic receiver based on two wave mixings in two nonlinear
Bi12SiO20 (BSO) photorefractive crystals
and its application for welded joints inspection. The nonlinear photo
refractive crystals are operated with inverted voltages in respect to each
other. Reversal of the voltage inverts the polarity of detected ultrasonic
pulses which are generated by a pulsed laser on a sample surface. Present noise
is, however, not inverted. Subtracting both signals after the two
photorefractive crystals using a balanced photo-detector leads to suppression
of noise and to an increase in the signal/noise ratio. We demonstrate the
working principle by using a phase modulator and present laser ultrasonic
measurement and compare the results from the proposed technique with a
conventional two wave mixing interferometer based on single BSO crystal showing
that the signal to noise/rate is significantly enhanced. Finally, we show the
experimental results of application of these detectors for defects detection in
two industrial samples with welded area.
Cite this paper
Zamiri, S. , Salfinger, M. , Gruber, M. , Stückler, M. and Reitinger, B. (2017). Photorefractive Ultrasonic Sensor for Weld Quality Monitoring. Open Access Library Journal, 4, e3597. doi: http://dx.doi.org/10.4236/oalib.1103597.
Honda,
T., Yamashita, T.
and
Matsumoto, H. (1995) Optical Measurement of Ultrasonic Nanometer
Motion of Rough Surface by Two-Wave Mixing in Bi12SiO20. Japanese Journal of Applied Physics, 34,
3737. https://doi.org/10.1143/JJAP.34.3737
Blouin, A. and Monchalin, J.P.
(1994) Detection of Ultrasonic Motion of a Scattering
Surface by Two-Wave Mixing in a Photorefractive GaAs Crystal. Applied Physics Letters, 65,
932. https://doi.org/10.1063/1.112153
Pouet, B.F., Ing, R.K., Krishnaswamy, S.
and
Royer, D. (1996) Heterodyne Interferometer with Two-Wave Mixing
in Photorefractive Crystals for Ultrasound Detection on Rough Surfaces. Applied Physics Letters, 69, 3782. https://doi.org/10.1063/1.116997
Hochreiner, A.,
Reitinger, B., Bouchal, K.D.,
Zamiri, S.,
Burgholzer, P. and Berer, T. (2013) Quasi-Balanced Two-Wave Mixing Interferometer
for Remote Ultrasound Detection. Journal
of Modern Optics, 60,
1327-1331. https://doi.org/10.1080/09500340.2013.837981
Girolamo, S.D.
and Kamshilin, A.A.
(2007) Fast Adaptive Interferometer on Dynamic Reflection
Hologram in CdTe:V. Optics Express, 15,
545-555. https://doi.org/10.1364/OE.15.000545
Blouin, A., Levesque, D., Neron, C.,
Enguehard,
F., Drolet, D.
and Monchalin, J.-P.
(1998) Review
of Progress in Qualitative Nondestructive Evaluation. Vol.
17, Plenum
Press, New York.
