Quasi-balanced two-wave mixing interferometer for remote ultrasound detection

Hochreiner, Armin; Reitinger, Bernhard; Bouchal, Klaus-Dieter; Zamiri, Saeid; Burgholzer, Peter; Berer, Thomas

doi:10.1080/09500340.2013.837981

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…The direction of the drift current depends on the direction of the applied external field. In a previous work [6] we presented that this leads to a relative shift between the two resulting space charge fields of π if the external voltage is larger than the diffusion field but smaller than the saturation field of the crystal. This effect finally results in a phase shift between reference and refracted beam of π/2 or 3π/2 for positive or negative voltages, respectively.…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…This effect finally results in a phase shift between reference and refracted beam of π/2 or 3π/2 for positive or negative voltages, respectively. Therefore, the polarity of the detected ultrasound signal can be inverted by reversion of the external field [6].…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…As sample a 3 mm thick aluminum plate was used. The sample To compare BLUS with a conventional TWM setup (based on single crystal) [6], we measured the noise amplitude of both setups for different detection power under similar experiment conditions. A half wave plate and a polarizing beam splitter were used to change the laser power.…”

Section: /10 Oalib Journalmentioning

confidence: 99%

“…The setup is based on balanced detection using two PRCs [5]. Ina quasi-balanced interferometer using a single BSO crystal was demonstrated by utilizing microcontrollers to invert the high voltage on the crystal after each measurement [6]. Thus always two individual measurements were necessary for operation.…”

Section: Introductionmentioning

confidence: 99%

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Photorefractive Ultrasonic Sensor for Weld Quality Monitoring

Zamiri¹,

Salfinger²,

Gruber³

et al. 2017

OALib

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We report on a laser ultrasonic receiver based on two wave mixings in two nonlinear Bi 12 SiO 20 (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. Subject AreasComposite Material, Material Experiment

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Section: Experiments and Discussionmentioning

confidence: 99%

Section: Experiments and Discussionmentioning

confidence: 99%

Section: /10 Oalib Journalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photorefractive Ultrasonic Sensor for Weld Quality Monitoring

Zamiri¹,

Salfinger²,

Gruber³

et al. 2017

OALib

View full text Add to dashboard Cite

show abstract

“…To alleviate the need for acoustical coupling, optical methods for detecting PA waves have been developed. Majority of these approaches rely on interferometric detection of the vibrations at the tissue surface resulting from the PA waves . Surface displacements are encoded as phase modulations in an optical beam (signal beam) incident at the sample surface.…”

Section: Introductionmentioning

confidence: 99%

A frequency‐domain non‐contact photoacoustic microscope based on an adaptive interferometer

George

Lloyd

Silverman

et al. 2018

Journal of Biophotonics

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A frequency-domain, non-contact approach to photoacoustic microscopy (PAM) that employs amplitude-modulated (0.1-1 MHz) laser for excitation (638-nm pump) in conjunction with a 2-wave mixing interferometer (532-nm probe) for non-contact detection of photoacoustic waves at the specimen surface is presented. A lock-in amplifier is employed to detect the photoacoustic signal. Illustrative images of tissue-mimicking phantoms, red-blood cells and retinal vasculature are presented. Single-frequency modulation of the pump beam directly provides an image that is equivalent to the 2-dimensional projection of the image volume. Targets located superficially produce phase modulations in the surface-reflected probe beam due to surface vibrations as well as direct intensity modulation in the backscattered probe light due to local changes in pressure and/or temperature. In comparison, the observed modulations in the probe beam due to targets located deeper in the specimen, for example, beyond the ballistic photon regime, predominantly consist of phase modulation.

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Non-contact detection of hidden damages in dispersive media using the instantaneous phase

Collazos-Burbano,

Ealo,

Orrego-Gonzalez

2023

J Braz. Soc. Mech. Sci. Eng.

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The assessment of dispersive media may become a challenge due to the high attenuation ratios, anisotropy and geometrical particularities of the specimen under study. Besides, non-contact methods that preserve the integrity of samples are needed when some degree of purity is required, e.g., when water immersion is not allowed, and the direct contact is not feasible. In this work, we study composite plates, in which acoustic dispersion is present. We use a non-contact hybrid optoacoustic system to implement the experimental setup that makes it possible the detection of the non-exposed damages of the samples. Different relevant aspects, such as cost, maximum frequency achieved, bandwidth, sensitivity, signal-to-noise ratio and spatial resolution were considered before setting the experimental configuration. Though dispersion curves are reconstructed, we emphasize the use of the instantaneous information of signals to detect the faults. Moreover, the instantaneous phase front of the acoustic field becomes a relevant complementary tool for ultrasonic inspection and characterization of dispersive media. In particular, it highlights hidden characteristics which are not visible with other commonly-used representations, namely, the instantaneous amplitude, the time-frequency distributions or the dispersion curves widely employed in non-destructive testing. This work provides an alternative approach to study highly attenuating media where the signal-to-noise ratio is a challenge, and the available scanning path is limited, e.g., layered and poroelastic media such as biological tissues.

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Quasi-balanced two-wave mixing interferometer for remote ultrasound detection

Cited by 6 publications

References 9 publications

Photorefractive Ultrasonic Sensor for Weld Quality Monitoring

Photorefractive Ultrasonic Sensor for Weld Quality Monitoring

A frequency‐domain non‐contact photoacoustic microscope based on an adaptive interferometer

Non-contact detection of hidden damages in dispersive media using the instantaneous phase

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