Acoustic interferometer

About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.

Measurement method and system utilizing ultrasonic wave

Abstract: A measurement method and system for measuring characteristics of attenuation of domains in an object comprises transmitting ultrasonic waves into the object and receiving ultrasonic waves reflected from the object. The measured characteristics of attenuation of reflected waves is determined using signal intensities. A plurality of ultrasonic waves having different frequencies are transmitted either simultaneously or alternately to an object, and the reflected waves are received from the object. The signal intensities corresponding to the transmission frequencies among the reflected waves are stored and the signal intensity ratio is calculated. The signal intensity ratio indicates the attenuation characteristic. The attenuation coefficient can also be obtained using a time interval from the transmission time to the time of the reflected wave is received. The attenuation slope can be obtained from this attenuation coefficient and the frequency difference between transmitted ultrasonic waves.

High-frequency monochromatic acoustic waves generated by laser-induced thermomodulation.

Abstract: Monochromatic acoustic waves are produced in a single crystal of PbMo${\mathrm{O}}_{4}$ by periodic heating of a deposited Au film over an area about 40 $\ensuremath{\mu}$m in diameter by two interfering single-frequency dye lasers. Detection of these waves at optical difference frequencies up to 4 GHz is accomplished by Brillouin scattering. The generated power depends on the film thickness by acoustic interference within the film. Besides weak phonon defocusing effects, the divergence of the generated acoustic wave is limited by Fraunhofer diffraction.

Peculiar transmission property of acoustic waves in a one-dimensional layered phononic crystal

Abstract: In this article, we report both theoretical calculation and experimental observation of acoustic waves abnormally through a one-dimensional layered transmitted phononic crystal at frequencies within the band gap into a material of large acoustic impedance mismatch, with an efficiency as high as unity. The transmission peaks can be interpreted as a result of the interference of acoustic waves reflected from all periodically aligned interfaces. The condition for the appearance of peaks is analyzed in detail and the optimized layer number is given for different configurations.