Time-reversal breaking of acoustic waves in a cavity.
- Resource Type
- Article
- Authors
- Bertaix, Vincent; Garson, Julien; Quieffin, Nicolas; Catheline, Stefan, ; Derosny, Julien; Fink, Mathias
- Source
- American Journal of Physics; Oct2004, Vol. 72 Issue 10, p1308-1311, 4p
- Subject
- Ultrasonic waves
Sound waves
Wave equation
Time reversal
Piezoelectric transducers
Piezoelectric devices
Physics
- Language
- ISSN
- 00029505
Acoustic time-reversal is a well-established technique that focuses an ultrasonic wave on the location of its source. It is based on the time-reversal invariance of the wave equation and is usually implemented using time-reversal mirrors made up of a hundred of piezoelectric transducers. However, a time-reversal experiment can be performed in a closed cavity (a water-filled beaker) with only one transducer as a pulse-echo system. This easy-to-build and low cost experiment involves students in the general concept of the time-reversal invariance of the wave equation. We show that it also can be adapted to become an ultrasonic time-reversal thermometer. A careful study of the focal point shows a dependence of its position as a function of temperature variations [ABSTRACT FROM AUTHOR]