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Showing papers on "Acoustic interferometer published in 1978"


Journal ArticleDOI
TL;DR: An analytical solution to the electric and acoustic fields generated by a surface charge source is obtained in this paper, where four types of acoustic waves can propagate along the surface of a general anisotropic medium.
Abstract: An analytical solution to the electric and acoustic fields generated by a surface charge source is obtained. As a result it is shown that four types of acoustic waves can propagate along the surface of a general anisotropic medium. Numerical examples are given for ST-cut quartz and rotated Y-cut X-propagating lithium niobate.

34 citations


Proceedings ArticleDOI
01 Jan 1978

15 citations



22 Sep 1978
TL;DR: In this paper, the relationship between predicted circumferential waves on cylinders and the normal-mode series solution for the acoustic scattering by submerged metal cylinders was determined, and this identification was used to experimentally detect the Rayleigh surface wave at low height.
Abstract: : The relationship is determined between predicted circumferential waves on cylinders and the normal-mode series solution for the acoustic scattering by submerged metal cylinders Specific circumferential waves are linked to the free modes of vibration of the cylinder, and this identification is used to experimentally detect the Rayleigh surface wave at low ka Circumferential waves on thin cylindrical shells are demonstrated to closely follow prediction based on Lamb theory for flat plates (Author)

12 citations


Journal ArticleDOI
TL;DR: In this paper, the authors show that strong acoustic waves can be generated when the velocity of the antenna was equal to the velocities of sound in the investigated liquid, where the antenna is moving in a liquid.
Abstract: Optoacoustic antennas moving in a liquid were produced experimentally and investigated. Strong acoustic waves were generated when the velocity of the antenna was equal to the velocity of sound in the investigated liquid.

12 citations



Journal ArticleDOI
TL;DR: An improved interferometer for monitoring Rayleigh waves is described, which can be employed with specular as well as diffuse reflecting surfaces to monitor surface deformations with the sensitivity of a Michelson interferometers.
Abstract: An improved interferometer for monitoring Rayleigh waves is described. Consisting of a light source, reflective grating, lens, and detector, the design is simple and inexpensive. It can be employed with specular as well as diffuse reflecting surfaces to monitor surface deformations with the sensitivity of a Michelson interferometer. By spinning the grating element, sensitivity variations with grating position are removed, resulting in stable operation. The interferometer response does vary with acoustic wavelength; a discussion of acoustic bandwidth shows that proper design can result in either a wide or narrow bandwidth response.

7 citations


Journal ArticleDOI
TL;DR: In this paper, a method of measuring the sound velocity in acoustooptic dynamic active solids has been investigated based on the fact that the velocity can be determined from the frequency difference between two resonant standing-wave modes in an acoustical interferometer.
Abstract: A method of measuring the sound velocity in acoustooptic d y active solids has been investigated. The method is based upon the fact that the velocity can be determined from the frequency difference between two resonant standing-wave modes in an acoustical interferometer. Instead of measuring the transformed acoustical impedance of the interferometer, the energy in the modes is probed with a laser beam, resulting in easy and accurate measurements. The method is applied to measure the sound velocity in germanium, which is the most utilized material in acoustooptical modulators for CO2-lasers. The velocity of a longitudinal acoustical wave propagation in the [11l]-direction in single crystal germanium was found to be 5481±6 m/s at room temperature.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the nature of the waves excited by positively biased probes in the "outskirt" region of a multi-dipole plasma device and concluded that the wave excited by the positively biased probe are the oblique ion-acoustic waves propagating at a large angle to the magnetic field lines.
Abstract: The nature of the waves excited by positively biased probes in the “outskirt” region of a multi-dipole plasma device is experimentally investigated. Measuring variations of the phase and amplitude of the waves along the lines parallel and perpendicular to the magnetic field we concluded that the waves excited by the positively biased probe are the oblique ion-acoustic waves i.e. the electrostatic ion-cyclotron waves in the low field limit propagating at large angle to the magnetic field lines. The conclusion is fortified by additional experiments performed on grid-excited ion-acoustic waves,

6 citations


Patent
20 Jan 1978
TL;DR: In this paper, a correlator is provided to judge the presence or not of any flaw of the position to be examined from the correlations of respective receiving acoustic waves by providing a correlation which judges the correlations from the propagation acoustic waves from a piezoelectric pulser.
Abstract: PURPOSE: To judge the presence or not of any flaw of the position to be examined from the correlations of respective receiving acoustic waves by providing a correlator which judges the correlations from the propagation acoustic waves from a piezoelectric pulser. CONSTITUTION: A piezoelectric pulser 2 is excited by the signal having amplified the output of an oscillator 5 with a power amplifier 6 and generates impulsive acoustic waves. The acoustic waves propagate in the member to be examined 1. Pizoelectric sensors 3, 4 are subsequently arrayed in the propagating direction of said acoustic waves and the acoustic waves are received respectively thereby. The receiving timings thereof vary with the time differences required for propagation of the acoustic wave in the member to be examined 1. And the signal having been received in the first piezoelectric sensor 3 is supplied to one terminal of a correlator 10. The signal having been received in the second piezoelectric sensor 4 is being inputted to the other terminal of the correlator 10. COPYRIGHT: (C)1979,JPO&Japio

6 citations



Proceedings ArticleDOI
01 Jan 1978

Journal ArticleDOI
TL;DR: In this paper, the propagation characteristics of acoustic surface waves in layered media are described and the strains caused in the film by thermal expansion can significantly affect the temperature coefficient of delay and the dispersion curves of velocity.
Abstract: The propagation characteristics of acoustic surface waves in layered media are described. The strains caused in the film by thermal expansion can significantly affect the temperature coefficient of delay and the dispersion curves of velocity. Computed results for an SiO2/LiTaO3 structure are compared with experimentally measured values.


Proceedings ArticleDOI
01 Jan 1978


Journal ArticleDOI
TL;DR: In this paper, the authors show how bulk waves are radiated by the charge source on the surface of a semi-infinite piezoelectric solid, and evaluate the expression for each component of bulk waves in the form of the Fourier integral, by assuming that the observation point is far from the source in comparison with a wavelength.
Abstract: A spurious response due to bulk waves has often been observed in surface-acoustic filters. This paper shows how bulk waves are radiated by the charge source on the surface of a semi-infinite piezoelectric solid. The expression for each component of bulk waves is evaluated asymptotically, in the form of the Fourier integral, by assuming that the observation point is located far from the source in comparison with a wavelength. In doing this, the method of steepest descents is used in order to integrate analytically. The numerical results are obtained for rotated Y-cut X-propagating LiNbO3 and Y-Z LiNbO3. These results are in good agreement with the experiment reported by Togami and Chiba.

Journal ArticleDOI
TL;DR: By measuring the dispersion relation of test waves in the plasma with the ion acoustic turbulence, Wang et al. as discussed by the authors found that the wave energy transferred from high frequencies to low frequencies and the phase velocity of ion acoustic wave becomes smaller than ion acoustic velocity in low frequencies near the peak of the turbulence spectrum.
Abstract: Ion acoustic turbulence is excited by the current-driven ion acoustic instability in a dc discharge plasma. By measuring the dispersion relation of test waves in the plasma with the ion acoustic turbulence, we find that the wave energy transfers from high frequencies to low frequencies and the phase velocity of the ion acoustic wave becomes smaller than the ion acoustic velocity in low frequencies near the peak of the turbulence spectrum. These experimental results can be interpreted theoretically.


Journal ArticleDOI
TL;DR: In this article, a simple polarization interferometry technique is introduced in acousto-optics, which allows a polarization discrimination of the light scattered by acoustic waves, when no strain-induced birefringence is produced by the acoustic perturbation.
Abstract: A simple polarization interferometry technique is introduced in acousto‐optics, which allows a polarization discrimination of the light scattered by acoustic waves, when no strain‐induced birefringence is produced by the acoustic perturbation. Results are presented, which are obtained through the use of a Savart plate in detecting light scattered by acoustic surface waves.