Noncontacting optical generation of focused surfaceacousticwaves using a customised zoneplate

Liu, M.; Ho, H.P.; Somekh, Michael Geoffrey; Weaver, John

doi:10.1049/el:19950216

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…We have reported previously on CGHs, which project an arc onto the surface of the sample, providing a diffraction-limited SAW ͑Rayleigh wave͒ focus. 5,6 These CGHs are analogous to using a refracting optical lens because they produce a continuous variation of the acoustic phase to effect the focusing. It is also possible to produce an analog of an optical diffractive CGH where control of the resulting beam is affected by discretely varying the phase of the ultrasonic source distribution.…”

Section: Introductionmentioning

confidence: 99%

Diffractive acoustic elements for laser ultrasonics

Clark

Sharples²,

Somekh³

2000

AIP Conference Proceedings

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Laser ultrasonics is an effective means of generating surface acoustic waves ͑SAWs͒. We have shown in previous publications how computer-generated holograms ͑CGHs͒ can be used to project optical distributions onto the sample surface. These can be used to control both the frequency content and the spatial distribution of the resulting ultrasound field. In this paper the concept is extended further to produce distributions which themselves act as diffractive acoustic elements ͑DAEs͒ for SAWs. It is demonstrated how frequency suppression, multiple foci, and frequency selective focusing of Rayleigh waves may be achieved with these elements. Agreement between the distributions predicted from the designs and those actually measured is excellent.

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Section: Introductionmentioning

confidence: 99%

Diffractive acoustic elements for laser ultrasonics

Clark

Sharples²,

Somekh³

2000

AIP Conference Proceedings

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“…In an earlier Letter [1] we showed that a focused acoustic beam could be produced using a customised zone plate; this focused the incoming light from the laser source into an arc which formed a focus of the surface acoustic waves (SAWs). Although images were obtained with this setup it was necessary to average the signal over many cycles in a digital oscilloscope to obtain a satisfactory signal to noise ratio.…”

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confidence: 99%

Non-contacting holographic surface acoustic wavemicroscope

et al. 1999

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Frequency control in laser ultrasound with computer generated holography

Clark

Linnane

Sharples

et al. 1998

Applied Physics Letters

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In laser ultrasonics a laser is used to excite ultrasonic waves. The intensity profile of the laser on the sample can be used to control the frequency of the ultrasound generated. In this letter we show how the frequency content of Rayleigh (surface acoustic) waves generated with an 82 MHz mode-locked laser can be controlled using computer generated holograms (CGHs). To demonstrate the effectiveness of the frequency control the CGHs used were defocused to generate new illumination profiles. The agreement between the actual and predicted amplitudes for these profiles is striking. Using this technique, the intensity output from the CGHs may be considered as a tunable Rayleigh wave source.

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Noncontacting optical generation of focused surfaceacousticwaves using a customised zoneplate

Cited by 5 publications

References 2 publications

Diffractive acoustic elements for laser ultrasonics

Diffractive acoustic elements for laser ultrasonics

Non-contacting holographic surface acoustic wavemicroscope

Frequency control in laser ultrasound with computer generated holography

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