Optical Detection of Ultrasound

Monchalin, Jean‐Pierre

doi:10.1109/t-uffc.1986.26860

Cited by 571 publications

(222 citation statements)

References 70 publications

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“…In order to detect the propagation of the ultrasonic pulses, a broad band electronic processing, similar to that used in the displacement measurements has been used in this experiment [12,13].…”

Section: Experimental Set-upmentioning

confidence: 99%

Detection of Leaky-Rayleigh Waves at Air-Solid Interfaces by Laser Interferometry

Adler¹,

Mattei²,

Billy³

et al. 1999

Review of Progress in Quantitative Nondestructive Evaluation

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Section: Experimental Set-upmentioning

confidence: 99%

Detection of Leaky-Rayleigh Waves at Air-Solid Interfaces by Laser Interferometry

Adler¹,

Mattei²,

Billy³

et al. 1999

Review of Progress in Quantitative Nondestructive Evaluation

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“…1. The out-of-plane motion (radial velocity component at the surface) was measured with a confocal Fabry-Perot interferometer [3,8]. Detailed discussions of the experimental methodology can be found in reference [8].…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…This method is noncontacting, requires no coupling medium, and operates directly on the surface of the specimen. Noncontacting ultrasonic detection using laser interferometers of several types has also been developed [3]. Laser techniques can achieve essentially point source and point detection of ultrasonic motion through focusing.…”

mentioning

confidence: 99%

Analysis of Laser Ultrasonic Measurements of Surface Waves on Elastic Spheres

Koo

Telschow

1992

Review of Progress in Quantitative Nondestructive Evaluation

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“…This is also an optieally-based approach, and leads to good detection sensitivity at a wide range of surfaces. The types of interferometers available have been reviewed by Monchalin [6], and there are now several devices available commercially. Recent advances in both heterodyne and Fabry-Perot designs now give good detection sensitivity, and with a pulsed laser source can lead to an NDE system that is capable of inspecting industrial materials [7].…”

Section: Types Of Detectorsmentioning

confidence: 99%

Pulsed Lasers for Quantitative Ultrasonic NDE

Hutchins

1992

Review of Progress in Quantitative Nondestructive Evaluation

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There has been a lot of recent interest in the use of pulsed lasers for the generation of ultrasound in a range of media [1], due to advantages inherent in the generation process. These include the non-contact nature of the method, and the generation of a wide bandwidth over a small source area. The size and shape of the source can also be changed using suitable optics, as can the generation mechanism itself. Generation MechanismsIn general, there are three types of source characteristics that are available. The first uses optical power densities that are below that required for melting of the irradiated solid surface. This results in a transient heating of the substrate, leading to rapid thermal expansion and the radiation of elastic waves. This is the so-called thermoelastic effect and the resulting waveforms and characteristics have been studied widely [e.g. 2,3]. The second type of generation mechanism can be created by removal of material from the surface of the sample. This can be by evaporation of a coating, applied to the surface prior to irradiation, or the ablation of the material itself [4]. In either case, the effect is to create a force due to material departing from the surface. This force tends to be pulse-like, unlike the thermoelastic ca se where the incoming laser energy is integrated to become a step. Where an applied coating is absent, a mixture of these two mechanisms can lead to a range of waveforms and source characteristics, as the power density at the surface is varied. This is due primarily to the formation of a plasma elose to the surface of e.g. a metal, which prolongs ablation at higher power densities.A third mechanism has recently been identified, which uses the effect of plasma formation close to a surface, but not intimately connected to it as in the ca se of a metal above. This occurs when there is a relatively high optical reflectivity, such as is present with far infra-red laser radiation (e.g. a C02 laser). Here, the reflected energy and incidence pulse can combine to induce breakdown of the air close to the surface, but at some distance from it [5] . Types of DetectorsIt is evident from the above that a pulsed laser can be a flexible method for the NDE of many materials. However, for it to be a truly useful method, it needs to be combined with adeteetion system that is itself non-contact and whieh has a wide bandwidth. The most popular recent choice for detection has been interferometry. This is also an optieally-based approach, and leads to good detection sensitivity at a wide range of surfaces. The types of interferometers available have been reviewed by Monchalin [6], and there are now several devices available commercially. Recent advances in both heterodyne and Fabry-Perot designs now give good detection sensitivity, and with a pulsed laser source can lead to an NDE system that is capable of inspecting industrial materials [7]. Interferometry has severallimitations -it tends to be expensive, and requires a certain reflectivity at the deteetion surface. Despite these li...

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Optical Detection of Ultrasound

Cited by 571 publications

References 70 publications

Detection of Leaky-Rayleigh Waves at Air-Solid Interfaces by Laser Interferometry

Detection of Leaky-Rayleigh Waves at Air-Solid Interfaces by Laser Interferometry

Analysis of Laser Ultrasonic Measurements of Surface Waves on Elastic Spheres

Pulsed Lasers for Quantitative Ultrasonic NDE

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