Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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60 citations
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TL;DR: In this paper, the authors introduce optical feedback interferometry as a simple and effective technique for the two-dimensional visualisation of acoustic fields and present imaging results for several pressure distributions including those for progressive waves, standing waves, as well as the diffraction and interference patterns of the acoustic waves.
Abstract: This study introduces optical feedback interferometry as a simple and effective technique for the two-dimensional visualisation of acoustic fields. We present imaging results for several pressure distributions including those for progressive waves, standing waves, as well as the diffraction and interference patterns of the acoustic waves. The proposed solution has the distinct advantage of extreme optical simplicity and robustness thus opening the way to a low cost acoustic field imaging system based on mass produced laser diodes.
60 citations
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01 Jan 1980
TL;DR: In this paper, the effect of rotation on surface acoustic waves was derived theoretically in a perturbation treatment of the Coriolis force for an isotropic medium, and the linear effect on the propagation velocity V in terms of (AV/V)/(R/w), where R and w are the rotation and SAN frequencies respectively, was found to depend only on the Poisson's ratio of the nediun and varies between.27 and -2.
Abstract: The effect of rotation on surface acoustic waves is derived theoretically in a perturbation treatment of the Coriolis force for an isotropic medium. The linear effect on the propagation velocity V in terms of (AV/V)/(R/w), where R and w are the rotation and SAN frequencies respectively, is found to depend only on the Poisson’s ratio of the nediun and varies between .27 and -.2. A dual-resonator gyroscope based on this effect will give a phase angle output equal to a maximum of 54% of the system attitude to be measured. The stability of the state-of-the-art commercial crystal oscillators implies a gyroscope resolution of 1/10 earth rotation rate.
58 citations
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12 Mar 1996TL;DR: In this paper, an absolute measurement is determined by a simple mathematical relationship between the measured wavelength and phase changes, where the phase change of the interference signal is continually detected during the wavelength modulation process.
Abstract: An absolute measuring interferometer having a measuring interferometer, a tunable laser emitting a laser beam and a control interferometer for adjusting the air wavelength of the laser beam. The control interferometer adjusts the air wavelength of the laser beam to a specific wavelength value at the ends of each measuring cycle. The wavelength of the tunable laser is continually tuned within the specific wavelength interval where the phase change of the interference signal is continually detected during the wavelength modulation process. An absolute measurement is determined by a simple mathematical relationship between the measured wavelength and phase changes.
58 citations
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TL;DR: In this article, the authors investigated the front surface detection of optoacoustic front surface transducers, where irradiation of the surface and detection of the acoustic wave take place on the same side of the sample.
Abstract: Thermoelastic waves generated by absorption of short laser pulses are used to characterize the layer structure of materials. The method is based on the analysis of the distribution of absorbed laser energy from temporal profiles of recorded acoustic signals. Particularly in view of noninvasive medical applications, optoacoustic front surface transducers are investigated in this study, where irradiation of the surface and detection of the acoustic wave take place on the same side of the sample. Front surface detection of optoacoustic waves is studied theoretically and experimentally, with special emphasis on acoustic diffraction and the differences between measurements in the acoustic near and far field. In the experiments, samples with stepwise and continuously varying depth profiles of absorption coefficient were irradiated with laser pulses of 6–8 ns duration. For the detection of the acoustic waves either an optical ultrasound sensor or an annular piezoelectric film was used. Generating the optoacousti...
57 citations