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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TL;DR: In this article, the phase shift of a guided acoustic wave propagating in transparent and isotropic solids is studied by optical interferometry via the photoelastic effect.
Abstract: Guided acoustic waves propagating in transparent and isotropic solids are studied by optical interferometry via the photoelastic effect. Unlike the photoelastic technique, the interferometric method permits the measurement of the phase shift rather than the polarization change of the light passing through an acoustic field. By analyzing the acoustically induced change in the index ellipsoid of refraction, it is demonstrated that the optical phase shift is proportional to the dilatation or the relative change in volume of the material. The dilatation fields of the symmetric and antisymmetric Lamb modes S0 and A0, as well as that of the Rayleigh wave, were calculated. Experiments performed in fused quartz by the interferometric method are in good agreement with theoretical predictions. Compared to the conventional photoelastic technique, the interferometric measurement of acoustic wave is phase sensitive and quantitative.
24 citations
TL;DR: In this article, a touch position sensing system including a transducer configured to transmit and modulate by pseudo random coding acoustic waves and to decode reflected waves generated by the acoustic waves by autocorrelating the pseudo-random coding is presented.
Abstract: A touch position sensing system including a transducer configured to transmit and modulate by pseudo random coding acoustic waves and to decode reflected waves generated by the acoustic waves by autocorrelating the pseudo random coding; a substrate configured to propagate the acoustic waves, including a touch surface having a first axis along a side of the perimeter of the substrate and a second axis which is perpendicular to the first axis and located along a second side of the perimeter; and, a first reflective array configured to reflect the acoustic waves transmitted by the transducer such that reflected waves are generated traveling parallel to the second axis, having a length substantially as long as the side of the perimeter corresponding to the first axis including partially reflective grating along the length and disposed lengthwise along the first axis of said substrate. Wherein, a touch to the touch surface attenuates the reflected waves such that said modulation by pseudo random coding of acoustic waves is varied, the transducer configured to detect the location of the touch based on variation in autocorrelation of the varied pseudo random coding included in the reflected waves.
24 citations
TL;DR: In this article, the existence of temperature hysteresis phenomena in a Fabry-Perot interferometer, resulting from a change in the refractive index of the inter-ferometer material when heated by CO2-laser radiation, was demonstrated.
24 citations
TL;DR: Theoretical computations have been carried out on ridge acoustic surface waves using the finite-element method in this paper, and the results obtained agree substantially with experiments performed previously, however, the results of the computations are different from those obtained in this paper.
Abstract: Theoretical computations have been carried out on ridge acoustic surface waves using the finite-element method. The results obtained agree substantially with experiments performed previously.
24 citations
01 Oct 2006
TL;DR: In this article, the authors present a straightforward method for measuring the longitudinal wave parameters of a bulk acoustic wave (BAW) resonator, including thickness, acoustic velocity and acoustic impedance of the various layers constituting the resonator.
Abstract: The workhorse of bulk acoustic wave (BAW) resonator design and analysis is the Mason model. This transmission line model takes as input parameters the thickness, (longitudinal) acoustic velocity and (longitudinal) acoustic impedance of the various layers constituting the resonator. Accurate knowledge of these parameters is essential for successful design and analysis of devices. In this paper we present a straightforward method for measuring these longitudinal wave parameters. Finally we will also make brief comments on how to evaluate the shear wave parameters
24 citations