Acoustic interferometer

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

Observed Classical Sound Absorption in Air

Abstract: A brief treatment of the theory and methods of measuring absorption of sound in gases precedes the data which are presented in the form of curves. The measurements were made with a Pierce acoustic interferometer at a frequency of 1927 kc/sec. in air. This frequency is high enough to satisfy Hardy's and Krasnooshkin's required conditions to obtain reliable results by this method. The experimental result agrees with Krasnooshkin's value of α0λ02 = (225 ± 5)(10)−6 cm.

Time-delay Fizeau phase-conjugate interferometer.

Abstract: A time-delay Fizeau phase-conjugate interferometer is constructed by using a BaTiO3 crystal in a degenerate four-wave-mixing configuration. The slow response time of BaTiO3 is used to build a phase-conjugate mirror that functions as a holographic memory. An optical wave and its time-delayed version are stored inside the crystal sequentially while their phase-conjugate waves are generated simultaneously. Superposition of the two phase-conjugate waves produces an interferogram as a result of the relative phase change of the input waves. The simplicity and real-time operation of this technique lead to several advantages over the conventional holographic interferometry. The use of photorefractive crystal eliminates the darkroom process and reposition procedure. A higher accuracy can be achieved because the interfering waves are phase-conjugate waves. The principle of this technique is presented and the experimental results and its applications are discussed.