Homodyne detection of ultrasonic surface displacements using two-wave mixing in photorefractive polymers

Klein, Martin; Bacher, G. D.; Grunnet‐Jepsen, A.; Wright, D.; Moerner, W. E.

doi:10.1016/s0030-4018(99)00023-1

Cited by 58 publications

(35 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For detection an IOS two-wave mixer laser interferometer detection sys- tem was used [21]. This is sensitive to the out-of-plane component of the wave motion, and has a bandwidth of 125 MHz with sensitivity from around 100 Hz.…”

Section: Experimental and Model Detailsmentioning

confidence: 99%

Non-contact ultrasonic detection of angled surface defects

Dutton

Clough

Rosli

et al. 2011

NDT & E International

View full text Add to dashboard Cite

Non-destructive testing is an important technique, and improvements are constantly needed. Surface defects in metals are not necessarily confined to orientations normal to the sample surface; however, much of the previous work investigating the interaction of ultrasonic surface waves with surface breaking defects has assumed cracks inclined at 90• to the surface. This paper explores the interaction of Rayleigh waves with cracks which have a wide range of angles and depths relative to the surface, using a non-contact laser generation and detection system. Additional insight is acquired using a 3D model generated using finite element method software. A clear variation of the reflection and transmission coefficients with both crack angle and length is found, in both the out-of-plane and in-plane components. The 3D model is further used to understand the contributions of different wavemodes to B-Scans produced when scanning a sample, to enable understanding of the reflection and transmission behaviour, and help identify angled defects. Knowledge of these effects is essential to correctly gauge the severity of surface cracking.

show abstract

Section: Experimental and Model Detailsmentioning

confidence: 99%

Non-contact ultrasonic detection of angled surface defects

Dutton

Clough

Rosli

et al. 2011

NDT & E International

View full text Add to dashboard Cite

show abstract

“…Laser detection typically uses interferometric techniques. Here, we report measurements using an IOS two-wave mixer interferometer [12]. This has a 125 MHz bandwidth, allowing measurements over a wide frequency range.…”

Section: Methodsmentioning

confidence: 99%

Detection and characterisation of surface cracking using scanning laser techniques

Edwards

Clough

Rosli

et al. 2012

AIP Conference Proceedings

View full text Add to dashboard Cite

Abstract. The use of lasers for generating and detecting ultrasound is becoming more established in non-destructive testing. However, there is still scope in developing the techniques to fully realise the benefits of non-contact measurements. One application is the detection of surface defects in metals; for example, rolling contact fatigue in rails, and surface cracking on billets or plates. We present measurements using a pulsed Nd:YAG laser to generate surface ultrasonic waves and an interferometer to detect the surface displacement on the sample, and investigate the interaction of Rayleigh or Lamb waves with surface defects. Signal enhancement in the near-field is observed for Rayleigh waves when either the generator or detector is close to a defect. For a scanned detector measurement, enhancement is observed due to constructive interference of the incident and reflected waves. For a scanned generator measurement, the change in generation conditions when the laser is over the defect also lead to an enhancement. In measurements of plate samples we observe similar enhancement effects whereby higher order modes are observed when the laser is above a defect. We discuss the implications of signal enhancements for detecting and characterising surface cracking.

show abstract

“…The system is based on an adaptive interferometer using two-wave mixing in a photorefractive crystal [10].…”

Section: Mid-infrared Laser Ultrasonic Testing Systemmentioning

confidence: 99%

Mid-IR laser ultrasonic testing for fiber reinforced plastics

Kusano

Hatano

Oguchi

et al. 2018

AIP Conference Proceedings

View full text Add to dashboard Cite

Abstract. Ultrasonic testing is the most common method to detect defects in materials and evaluate their sizes and locations. Since piezo-electric transducers are manually handled from point to point, it takes more costs for huge products such as airplanes. Laser ultrasonic testing (LUT) is a breakthrough technique. A pulsed laser generates ultrasonic waves on a material surface due to thermoelastic effect or ablation. The ultrasonic waves can be detected by another laser with an interferometer. Thus, LUT can realize instantaneous inspection without contacting a sample. A pulse laser with around 3.2 in the mid-IR range) is more suitable to generate ultrasonic waves for fiber reinforced plastics (FRPs) because the light is well absorbed by the polymeric matrix. On the other hand, such a laser is not available in the market. In order to emit the mid-IR laser pulse, we came up with the application of an optical parametric oscillator and developed an efficient wavelength conversion device by pumping a compact Nd:YAG solid-state laser. Our mid-IR LUT system is most suitable for inspection of FRPs. The signal-to-noise ratio of ultrasonic waves generated by the mid-IR laser is higher than that by the Nd:YAG laser. The purpose of the present study is to evaluate the performance of the mid-IR LUT system in reflection mode. We investigated the effects of the material properties and the laser properties on the generated ultrasonic waves. In addition, C-scan images by the system were also presented.

show abstract

Homodyne detection of ultrasonic surface displacements using two-wave mixing in photorefractive polymers

Cited by 58 publications

References 17 publications

Non-contact ultrasonic detection of angled surface defects

Non-contact ultrasonic detection of angled surface defects

Detection and characterisation of surface cracking using scanning laser techniques

Mid-IR laser ultrasonic testing for fiber reinforced plastics

Contact Info

Product

Resources

About