|Auteur(s):||A. Tourin, A. Derode and M. Fink
|Titre:||Temperature sensitivity of Time-Reversal focusing in a complex medium
|Référence:||World Congress on Ultrasonics, pp 851-853, 2003
|Type de publication:||Communication à un congrès avec actes
|Soumis en Septembre 2003, accepté en Septembre 2003 et publié en Novembre 2003|
We present time-reversal focusing experiments in an open multiple scattering medium undergoing a temperature change. Multiply scattered waves are recorded once to define a reference, then time-reversed and continuously backpropagated into the medium while the temperature decreases slowly. The temporal shift of the time-reversed peak enables to retrieve changes in temperature as small as 0.02° C, while the peak amplitude decays with temperature in a manner which is well predicted by a simple “shot noise” model. We also show that the sensitivity to a change of temperature increases with the scattering order (i.e. time), which cannot be accounted for by the shot-noise model, and is probably due to the elastic resonances of the scatterers, which result in a time-dependent phase variance in the scattered signals.
time-reversal multiple scattering temperature DWS
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