Results 131 to 140 of about 1,443 (165)
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LASER PICOSECOND ULTRASONIC MEASUREMENT OF LONGITUDINAL SOUND VELOCITY IN NANOMETER THIN FILMS
AIP Conference Proceedings, 2008We demonstrate applications of ultrafast‐laser‐based picosecond ultrasonic techniques to sound velocity measurement in nanometer thin films. The longitudinal sound velocities in various thin films (100∼300 nm thick) were directly determined by pulse‐echo technique.
N. W. Pu +3 more
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Sensitive detection of laser damage to Mo/Si multilayers by picosecond ultrasonics
Applied Physics B, 2004Picosecond ultrasonics is used to study the damage or degradation of Mo/Si multilayers caused by laser irradiation. Changes of surface phonon spectra in multilayers due to femtosecond laser damaging are observed in a regime of extremely low fluence level, well before the onset of melting, delamination, distortion, or material interdiffusion.
N.-W. Pu, E.-Y. Pan, J. Bokor
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The European Physical Journal Special Topics, 2008
Picosecond laser ultrasonics uses femtosecond laser pulses for the generation and detection of acoustic pulses with a typical duration between few picoseconds and few hundreds of pico seconds. The shorter the duration of the acoustic pulse is, the more precisely could be made the measurements of the film thickness [C. Thomsen et al., Phys. Rev.
C. Mechri +7 more
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Picosecond laser ultrasonics uses femtosecond laser pulses for the generation and detection of acoustic pulses with a typical duration between few picoseconds and few hundreds of pico seconds. The shorter the duration of the acoustic pulse is, the more precisely could be made the measurements of the film thickness [C. Thomsen et al., Phys. Rev.
C. Mechri +7 more
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The Journal of the Acoustical Society of America, 2011
Research results on the characterization of the thin (submicrometers thick) films of the nanostructured materials by the experimental methods of picosecond laser ultrasonics are reviewed. These methods make use of femtosecond lasers to generate and to detect GHz–THz acoustic waves.
V. Gusev, P. Ruello
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Research results on the characterization of the thin (submicrometers thick) films of the nanostructured materials by the experimental methods of picosecond laser ultrasonics are reviewed. These methods make use of femtosecond lasers to generate and to detect GHz–THz acoustic waves.
V. Gusev, P. Ruello
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Imaging of 3D acoustic wave-fronts by means of picosecond laser ultrasonics in GaAs substrate
The Journal of the Acoustical Society of America, 2008Picosecond ultrasonic experiments are widely used as pump-probe technique using longitudinal acoustic pulses and measuring time dependence of the signal. We present an experiment which combines an interferometer with the control of the pump-probe spatial overlap.
Emmanuel Péronne +4 more
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IEEE Symposium on Ultrasonics, 2003, 2004
In this paper, the effects of the laser pulse duration (100 fs - 12 ps) are investigated on the generation and the detection of photo-acoustic signals. A model of generation and detection of ultrasonic waves with ultra-shorts laser pulses is presented.
Rossignol, C. +4 more
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In this paper, the effects of the laser pulse duration (100 fs - 12 ps) are investigated on the generation and the detection of photo-acoustic signals. A model of generation and detection of ultrasonic waves with ultra-shorts laser pulses is presented.
Rossignol, C. +4 more
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2006 IEEE Ultrasonics Symposium, 2006
The control of the frequency is a challenging question for the mass production of bulk acoustic wave (BAW) filters. It passes through a precise control of mechanical properties of the active layer but also of the thicknesses of the whole stack. But performing mechanical measurements at such a scale is not so easy and we may say that BAW resonators ...
P. Ancey, A. Devos, P. Emery, G. Caruyer
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The control of the frequency is a challenging question for the mass production of bulk acoustic wave (BAW) filters. It passes through a precise control of mechanical properties of the active layer but also of the thicknesses of the whole stack. But performing mechanical measurements at such a scale is not so easy and we may say that BAW resonators ...
P. Ancey, A. Devos, P. Emery, G. Caruyer
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Effect of the laser pulse duration on picosecond ultrasonic signals
2005no ...
Rossignol, C. +4 more
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Journal of Applied Physics, 1999
This article describes the use of optical methods based on picosecond transient gratings to stimulate and detect ultrasonic acoustic modes in several important structures with dimensions less than ∼200 μm: single-mode optical fiber, cylindrical microcapillary tubes, and planar microfluidic networks.
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This article describes the use of optical methods based on picosecond transient gratings to stimulate and detect ultrasonic acoustic modes in several important structures with dimensions less than ∼200 μm: single-mode optical fiber, cylindrical microcapillary tubes, and planar microfluidic networks.
openaire +1 more source