Coherent backscattering of ultrasound without a source

Éric Larose (1, 2) , Oleg I. Lobkis (1) , Richard L. Weaver (1)

1 TA&M - Department of Theoretical and Applied Mechanics
2 LGIT - Laboratoire de Géophysique Interne et Tectonophysique

Coherent backscattering is due to constructive interferences of reciprocal paths and leads to an enhancement of the intensity of a multiply scattered field near its source. To observe this enhancement an array of receivers is conventionally placed close to the source. Our approach here is different. In a first experiment, we recover the coherent backscattering effect (CBE) within an array of sources and a distant receiver using time correlation of diffuse fields. The enhancement cone has an excellent spatial resolution. The dynamics of the enhancement factor is studied in a second experiment using correlation of thermal phonons at the same ultrasonic frequencies, without any active source.

Domaines: Autre [cond-mat.other]; Vibrations [physics.class-ph]; Acoustique [physics.class-ph]; Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Mécanique statistique [cond-mat.stat-mech]

Éric Larose, Oleg I. Lobkis, Richard L. Weaver. Coherent backscattering of ultrasound without a source. EPL - Europhysics Letters, 2006, 76 (3), pp.422-428. ⟨hal-00173269⟩