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Showing papers on "Acoustic interferometer published in 1967"


Journal ArticleDOI
TL;DR: Proportional velocity of pressure and sound in rocks by pulse transmission methods, determining time delay by means of frequency counter as discussed by the authors was used to determine the time delay of a pulse transmission.
Abstract: Proportional velocity of pressure and sound in rocks by pulse transmission methods, determining time delay by means of frequency counter

120 citations


Journal ArticleDOI
TL;DR: In this paper, the generation of acoustic waves by rf electromagnetic radiation was studied, and its effect on the surface impedance of metals was evaluated, and the effect of metal surface impedance on acoustic wave propagation was evaluated.

46 citations


Journal ArticleDOI
01 Feb 1967
TL;DR: In this article, the optical heterodyne detection of the diffracted light was shown to be in approximate agreement with theoretical predictions, and experimental observations were shown to match theoretical predictions.
Abstract: Diffraction of light by surface acoustic waves in quartz is reported. Optical heterodyne detection of the diffracted light is described. Experimental observations are shown to be in approximate agreement with theoretical predictions.

42 citations



Journal ArticleDOI
TL;DR: In this paper, a single crystal aluminium sample was used as an acoustic resonant cavity excited by strongly attenuated helicon waves, and quantum oscillations were observed in the r.f.

28 citations


Journal ArticleDOI
TL;DR: In this article, the authors generalized the classical investigation of radiative damping of sound waves by Stokes to the case of arbitrary ratio of acoustic wavelength to photon mean free path.
Abstract: The classical investigation of radiative damping of sound waves by Stokes is generalized to the case of arbitrary ratio of acoustic wavelength to photon mean free path.

14 citations



Journal ArticleDOI

12 citations


Journal ArticleDOI
TL;DR: In this article, the omnidirectional scattering of acoustic waves by a rough, imperfectly reflecting surface is described using the method of physical optics, and the expression for the farzone intensity is derived and then specialized to the case of surfaces that are sufficiently rough to neglect the specularly reflected power.
Abstract: The omnidirectional scattering of acoustic waves by a rough, imperfectly reflecting surface is described using the method of physical optics. The expression for the far‐zone intensity is derived and then specialized to the case of surfaces that are sufficiently rough to neglect the specularly reflected power. For such surfaces, the average differential scattering cross section σ0 is calculated and compared with the results of bistatic measurements made under conditions that satisfy the assumptions of the theory.

9 citations


Proceedings ArticleDOI
08 May 1967
TL;DR: The existence of materials having a very low acoustic loss per wavelength, and the recent marked advances in the performance of transducers at microwave frequencies, suggest that it might prove possible to construct microwave components using acoustic waves as mentioned in this paper.
Abstract: The existence of materials having a very low acoustic loss per wavelength, and the recent marked advances in the performance of transducers at microwave frequencies, suggest that it might prove possible to construct microwave components using acoustic waves. The main attraction of this possibility is seen to lie in the size reduction, by a factor of 10/sup 5/, which is implied.

8 citations


Journal ArticleDOI
TL;DR: In this paper, the authors calculated the line profiles to be expected when a Fabry-Perot interferometer is used to measure absorption lines and showed that large errors may be introduced in the measurement of the integrated absorption, even when an interferometry of high finesse is used.
Abstract: We have calculated the line profiles to be expected when a Fabry–Perot interferometer is used to measure absorption lines. We have shown that large errors may be introduced in the measurement of the integrated absorption, even when an interferometer of high finesse is used. Curves and tables are given for finding the true absorption width and the true peak absorption from the apparent values observed under different operating conditions of the emission light source and the interferometer. We show qualitatively that the distortions are partially due to the presence of nonzero wings in the instrument-bandpass function. Finally, we show a Fourier series expansion of the integral giving the transmittance of the Fabry-Perot interferometer when absorbing atoms are in the light path.

Journal ArticleDOI
TL;DR: The velocity of sound in liquid argon and liquid krypton has been measured in the temperature range between their normal boiling points and their triple points, using a tube acoustic interferometer as mentioned in this paper.
Abstract: The velocity of sound in liquid argon and liquid krypton has been measured in the temperature range between their normal boiling points and their triple points, using a tube acoustic interferometer. The results for argon agree with those of most other investigators to within 0.2%. There are no velocity data for liquid krypton. Compressibilities for these liquids have been calculated, using available density data.The results were analyzed, using a law of corresponding-states treatment in the temperature interval under consideration. To within the limits of uncertainty in the Lennard-Jones 6:12 potential parameter e, the law is found to be obeyed.

Journal ArticleDOI
TL;DR: Propagation of shear acoustic waves traveling parallel to magnetic field along symmetry direction in metal crystal has been studied in this paper, where the authors show that acoustic waves can propagate parallel to the magnetic field.
Abstract: Propagation of shear acoustic waves traveling parallel to magnetic field along symmetry direction in metal crystal




Journal ArticleDOI
TL;DR: In this paper, an acoustic Fabry-Perot interferometer was constructed using two air-backed xcut quartz transducers submerged in water, driving one around its 3MHz resonance, and examining the frequency spectrum across the other with a spectrum analyzer.
Abstract: Korpel and Adler showed that above a certain energy‐density threshold in an intense ultrasonic standing wave that subharmonics of the driving frequency were present [Appl. Phys. Letters, 7, 106 (1965)]. To study this effect, an acoustic Fabry‐Perot interferometer was constructed using two air‐backed x‐cut quartz transducers submerged in water, driving one around its 3‐MHz resonance, and examining the frequency spectrum across the other with a spectrum analyzer. An investigation of thresholds and frequencies of the subharmonic waves was conducted for various configurations of reflectors, driving frequencies, and distances between reflectors. All subharmonics observed had frequencies that are integer harmonics of the fundamental cavity resonance. The frequencies of the subharmonic “modes” occur in hands around 12, 13, and 14 of the driving frequency, but it should be noted that this does not necessarily imply that subharmonics occur at 1/n of the driving frequency. [Sponsored by the Office of Naval Research.]


Journal ArticleDOI
01 Jan 1967
TL;DR: In this paper, the energy density of longitudinal waves in a homogeneous plasma is found from a general theory for sound waves in dispersive media, which is then interpreted as the acoustic version of the harmonic Poynting theorem in electromagnetism.
Abstract: The energy density of longitudinal waves in a homogeneous plasma is found from a general theory for sound waves in dispersive media. The energy relation of Lonngren is then interpreted as the acoustic version of the harmonic Poynting theorem in electromagnetism.

Journal ArticleDOI
S. N. Samaddar1
TL;DR: In this paper, the authors considered the possibility of excitation of lateral waves in a hot plasma in contact with a perfectly conducting boundary by a mechanical body source and showed that these electro-acoustic lateral waves can be excited also by an electric dipole oriented in the same direction as the source.
Abstract: This paper considers the possibility of excitation of lateral waves in a hot plasma in contact with a perfectly conducting boundary by a mechanical body source. These lateral waves being incident on the conducting surface at a critical angle from the source travel a certain distance along the surface with the phase velocity of light in a cold plasma and the waves are then reflected back at the critical angle to the observer in the compressible plasma. The incident and reflected portions of the path are traversed by the waves with the phase velocity of an acoustic wave in a compressible plasma. It is shown that these electro-acoustic lateral waves can be excited also by an electric dipole oriented in the same direction as the mechanical body source. The amplitudes of the waves excited by these two different sources are compared.