Laura Cobus Colloquium

Fri. Apr. 1 12:30 PM - Fri. Apr. 1 01:20 PM
Location: 1L07

Laura Cobus, University of Manitoba

Time Reversal of Ultrasound: From Applied Imaging to Pure Physics Research

The concept of time-reversal invariance is at the heart of acoustic wave transport. While waves in inhomogenous media are often difficult to control, time-reversal techniques can focus ultrasound remarkably well through such materials. In this talk, the basics of time-reversal and its use in target detection with ultrasound are presented. An iterative time-reversal process can be used to automatically identify and sort different targets in the medium. Experimentally, this is accomplished using multi-element ultrasonic arrays, which can be used to gather a propagation matrix of responses between sources and receivers. With this data, even more sophisticated imaging can be performed by combining iterative time-reversal with random matrix methods. Interestingly, these same techniques can also be applied to study ultrasound in very strongly scattering media, where exotic and rare wave phenomena can occur. I will discuss how this approach, originally developed for simple target detection, has recently led to some new advances in fundamental wave physics.