Holographic interferometry with a phase-modulated reference beam is applied to an acoustic holography. A very thin, flexible, optically reflective membrane, called a pellicle, is used in the liquid as an acousto-optic interface. The method involves three processes: the motion of a pellicle caused by an ultrasonic wave is recorded as an optical hologram using holographic interferometry; the opti...

Sound can be described as the propagation of pressure variations in compressible media that involves compression and expansion and induces a change in the density of the medium. This change in acoustic pressure as it induces a change of the refractive index can be measured by optical methods, the most recent being the optical feedback interferometry. With this technique, a laser diode is beamin...

Existing techniques in correlation spectroscopy, such as coda wave interferometry and diffusing acoustic wave spectroscopy, determine the average motion of scatterers or change in the propagation velocity from the temporal change of multiply scattered sound. However, neither of them gives an indication of the spatial extent of the change in the medium. This study is an extension of the techniqu...

A new method of generating shear waves with near-optical wavelength has been developed for gigahertz ultrasonic interferometry. The new acoustic technique features a P-to-S conversion upon reflection inside an MgO buffer rod, and is used first to determine the full set of ambient P–T elastic constants (ci j ) of magnesiowüstite—(Mg, Fe)O. In addition, P-wave travel times have been measured in o...

Interferometry allows for synthesis of data recorded at any two receivers into waves that propagate between these receivers as if one of them behaves as a source. This is accomplished typically by crosscorrelations. Based on perturbation theory and representation theorems, we show that interferometry also can be done by deconvolutions for arbitrary media and multidimensional experiments. This i...