Refocusing with Time Reversal Mirror in Random Medium

Adaptive time-reversal mirror.

The time-reversal mirror uses the received signal from a probe source to refocus the signal at the probe source location by backpropagating the time-reversed version of the received signal. In this study, an adaptive method is described to steer a null to an arbitrary position in a waveguide while maintaining a distortionless response at the probe source location. As an application, selective f...

Time Reversal and Refocusing in Random Media Guillaume Bal and Leonid

Ocean Acoustic Time-reversal Mirror

Two ocean acoustics experiments demonstrating the implementation of a time reversal mirror have been conducted. Pulsed sound (50-ms with center frequency 445 Hz) was refocused to the position of a probe source out to ranges as great as 30 km in 125-m deep water. In addition, a technique to refocus at ranges other than that of the probe source also was demonstrated. These results are summarized ...

Time Reversal Refocusing for Point Source in Randomly Layered Media

This paper demonstrates the interest of a time-reversal method for the identification of source in a randomly layered medium. An active source located inside the medium emits a pulse that is recorded on a small time-reversal mirror. The wave is sent back into the medium, either numerically in a computer with the knowledge of the medium, or physically into the real medium. Our goal is to give a ...

A time-reversal mirror with variable range focusing

Recently a time-reversal mirror ~or phase-conjugate array! was demonstrated experimentally in the ocean that spatially and temporally refocused an incident acoustic field back to the original position of the probe source @Kuperman et al., J. Acoust. Soc. Am. 103, 25–40 ~1998!#. Here this waveguide time-reversal mirror technique is extended to refocus at ranges other than that of the probe sourc...