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Multiplexing Focused Ultrasound Stimulation with Fluorescence Microscopy
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Time reversal of ultrasonic fields. I. Basic principles.

M Fink1

  • 1Lab. Ondes et Acoustique, Paris VIII Univ.

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
|January 1, 1992
PubMed
Summary
This summary is machine-generated.

Time reversal of ultrasonic fields focuses waves through complex media using a time-reversal mirror (TRM). This optimal method acts as a matched filter for precise acoustic focusing and target analysis.

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Area of Science:

  • Acoustics
  • Wave Propagation
  • Signal Processing

Background:

  • Focusing ultrasonic waves through inhomogeneous media presents significant challenges.
  • Classical adaptive time-delay techniques offer partial solutions but can be complex.
  • Time reversal offers a novel approach to overcome these limitations.

Purpose of the Study:

  • To demonstrate the efficacy of time reversal for focusing ultrasonic fields through inhomogeneous media.
  • To introduce and explain the principles of the time-reversal mirror (TRM).
  • To explore advanced concepts like time-reversal cavities and iterative processing.

Main Methods:

  • Utilizing a time-reversal mirror (TRM) composed of transmit-receive transducers.
  • Sampling incident acoustic pressure and re-emitting the time-reversed field.
  • Applying principles of reciprocity in inhomogeneous media.

Main Results:

  • Time-reversal focusing is shown to be optimal, acting as a spatial-temporal matched filter.
  • The TRM successfully focuses ultrasonic waves through inhomogeneous media onto reflective targets.
  • New concepts like time-reversal cavities and iterative processing were developed.

Conclusions:

  • Time reversal is an effective method for focusing ultrasonic fields through inhomogeneous media.
  • The TRM provides an optimal solution for acoustic focusing and target characterization.
  • Advanced time-reversal techniques enable enhanced target analysis and manipulation.