All-optical probing of the nonlinear acoustics of a crack

Mézil, Sylvain; Chigarev, Nikolay; Tournat, Vincent; Gusev, Vitalyi

doi:10.1364/ol.36.003449

Cited by 29 publications

(31 citation statements)

References 19 publications

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“…Abrupt variations and=or saturation of the amplitudes of reflected and transmitted skimming longitudinal waves and Rayleigh waves mode-converted from the skimming longitudinal waves, observed in our experiments at heating power approaching 170 mW, are the indications of the threshold character of the local crack closing, which has been also recently observed in other nonlinear photoacoustic experiments with laser-heated cracks. 21,22 By solving numerically the problem of glass heating by penetrating laser radiation, 26 we have estimated that at a 170 mW heating power the maximum temperature rise is about 180 C while the maximum relative displacement of the crack faces, that can be caused by the thermoelastic stresses, is about 300 nm. The comparison of the latter value with the maximum crack widths of 350-400 nm at the surface, which were measured by atomic force microscope, provides very strong indication that in our experiments, nearly complete local closure of the cracks is achieved at heating power above 170 mW.…”

Section: Discussionmentioning

confidence: 99%

“…20,21 Finally, quite recently all-optical probing of the nonlinear acoustics of a crack has been experimentally realized. 22 Crack-probing acoustic waves were initiated by the absorption of radiation from a pair of continuous laser beams intensity modulated at two different frequencies. The detection of acoustic waves at mixed frequencies (absent in the frequency spectrum of the heating lasers) was achieved by optical deflectometry or interferometry.…”

Section: Introductionmentioning

confidence: 99%

“…23 In this letter we report all-optical evaluation of real surface-breaking crack nonlinearity using quasi-continuous laser heating of the crack to induce changes in its elasticity and using laser-generated and laser-detected acoustic pulses, propagating along the material surface, to probe the crack. In comparison with the all-optical frequency-domain technique, 22 based on the harmonically modulated cw lasers and taking an advantage of the acoustical resonances of the crack-containing sample for the detection of nonlinear effects, the time-domain technique presented below is potentially faster for imaging applications.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves

Ni¹,

Chigarev²,

Tournat³

et al. 2012

The Journal of the Acoustical Society of America

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All-optical monitoring of the nonlinear motion of a surface-breaking crack is reported. Crack closing is induced by quasi-continuous laser heating, while Rayleigh surface acoustic pulses and bulk longitudinal surface skimming acoustic pulses are also generated and detected by lasers. By exploiting the strong dependence of the acoustic pulses reflection and transmission efficiency on the state-open or closed-of the contacts between the crack faces, the parametric modulation of ultrasonic pulses is achieved. It is observed that bulk acoustic waves skimming along the surface can be more sensitive to crack motion than Rayleigh surface waves.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves

Ni¹,

Chigarev²,

Tournat³

et al. 2012

The Journal of the Acoustical Society of America

Self Cite

View full text Add to dashboard Cite

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“…[1][2][3][4][5][6][7][8][9] All practical LU systems must optimize both transmit (pump) and receive (probe) paths for a given application. Transmit pulses are usually generated through laser-induced, non-stationary heating of a target and its subsequent thermal expansion.…”

Section: Introductionmentioning

confidence: 99%

A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites

Pelivanov¹,

Buma²,

Xia³

et al. 2014

Journal of Applied Physics

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Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for non-destructive testing and evaluation of aircraft composites. The performance of the LU system is demonstrated on a composite sample with known defects. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed fiber laser delivering nanosecond laser pulses at a repetition rate up to 76 kHz rate with a pulse energy of 0.6 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals at the same point on the composite surface. A-and B-scans obtained with the Sagnac interferometer are compared to those made with a contact wide-band polyvinylidene fluoride transducer. V C 2014 AIP Publishing LLC. [http://dx

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“…However, the reports on the imaging of the cracks or on the attempts of their imaging are much rarer. [14][15][16][17][18][19][20][21][22][23][24][25][26] We believe that this situation is, at least partially, caused by the fact that for the crack detection it is sufficient to detect a nonlinear signal just from one point of the crack with the highest nonlinearity, while for the imaging of the crack, it is necessary to initiate the nonlinear scattering phenomena along complete length of the crack, i.e., even in its parts with lowest nonlinearity. Obviously, this would, in general, require higher amplitudes of the acoustic fields for imaging than for the detection.…”

mentioning

confidence: 99%

Two dimensional nonlinear frequency-mixing photo-acoustic imaging of a crack and observation of crack phantoms

Mézil

Chigarev

Tournat

et al. 2013

Journal of Applied Physics

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A two-dimensional imaging of a crack by nonlinear frequency-mixing photo-acoustic method is reported. The imaging contrast is due to nonlinear photo-thermo-acoustic processes taking place in case of simultaneous excitation by lasers of thermo-elastic and acoustic waves in the vicinity of the cracks. The images are obtained by scanning of two co-focused laser beams in region of crack location. The first cw laser beam, modulated in intensity at low frequency f L , generates a thermoelastic wave, which is able to strongly periodically modulate the local crack rigidity up to complete closing/opening of the crack. The second cw laser beam, intensity modulated at much higher frequency f H , generates an acoustic wave incident on the breathing crack. The crack rigidity is also influenced by the stationary non-modulated inhomogeneous thermal stresses caused by the stationary heating of the sample by both lasers. The main contribution to imaging contrast comes from the strong dependence of the reflectivity of acoustic waves on the crack rigidity. The modulation of crack rigidity by thermo-elastic wave leads to the parametric modulation of the reflected acoustic waves and the generation in the spectrum of the acoustic field of the side lobes, which are separated from f H by the integer number of f L . Scan images of a crack with an amplitude dynamics up to 40 dB and a spatial resolution better than 100 lm, are obtained through the mapping of nonlinear side lobe amplitudes. The observed dependences of the images on the power of the lasers are discussed and the physical explanation of the appearance of crack phantom images at high level of optical excitation is proposed. For comparison and elucidation of spatial resolution issues related to this imaging method, the one-dimensional images, obtained with one laser beam focus position fixed and the second beam focus position scanning, are also presented and discussed.

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All-optical probing of the nonlinear acoustics of a crack

Cited by 29 publications

References 19 publications

Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves

Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves

A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites

Two dimensional nonlinear frequency-mixing photo-acoustic imaging of a crack and observation of crack phantoms

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