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arXiv · 0804.2355

Time-reversal of a wave packet emitted by an internal source: the perfect inverse filter

Hernan L. Calvo·Horacio M. Pastawski
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Abstract

The time-reversal mirror (TRM) of acoustic waves is used as a focusing technique that is robust against disorder and chaos. The propagation of an ultrasonic pulse from the focal point is detected and recorded by a surrounding array of transducers that enclose the cavity region. The registered signals are then played-back in the reverse temporal sequence and an imperfect Loschmidt echo is obtained. A similar technique developed in the quantum domain, the perfect inverse filter (PIF), ensures an exact reversion. Applied to the acoustical case, it allows an improvement in the design of a minimally invasive inverse filter. Although that version of PIF accounts for external source condition, now we propose a generalization where the initial excitation is created inside the cavity. We present the theoretical principles for this form of PIF and perform a numerical test in a multichannel system that improves the focalization quality compared to the TRM version.

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Hernan L. Calvo, Horacio M. Pastawski. 2008-04-15. Time-reversal of a wave packet emitted by an internal source: the perfect inverse filter. https://arxiv.org/abs/0804.2355

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