Waves in Complex Media

We study the properties of waves in complex materials where the waves are scattered many times before leaving the medium. Wave phenomena in these systems can be radically different to those normally associated with waves, and are attracting growing interest. We use innovative ultrasonic techniques, developed in our laboratory, to study these wave phenomena for acoustic and elastic waves. Our goals are both to discover and understand novel aspects of wave propagation in strongly scattering media, and to use our knowledge of wave scattering to develop new experimental probes of the structure and dynamics of strongly scattering materials.

We also use our ultrasonic techniques to study a wide range of mesoscopic materials, whose physical properties are determined by internal structures on length scales intermediate between atomic dimensions and bulk. Some examples include fluidized suspensions, phononic crystals, porous materials, and biological materials of importance in food science (see our current research page or read our publications).

We welcome students and postdocs who are interested in joining our group. We offer excellent support and training; over the last few years, this has helped several of our students to win prestigious national awards. Our students also benefit from collaborations with outstanding scientists at other institutions, including leading universities in the USA, Europe and Asia. Our graduates are well qualified for jobs in industry, national labs and universities.

We also welcome visiting scientists and students from other research groups, both at universities and industry, who would like to make use of our facilities and expertise in ultrasonics. We encourage anyone with an interest in our research program to contact us.

 Dynamic Speckle Pattern

Dynamic Speckle Pattern

When ultrasonic waves travel through a strongly scattering, random medium, they interfere to form a speckle pattern in which the intensity fluctuates across the output face of the sample. This animation shows how the pattern evolves in time during a pulsed experiment, as the pulse travels longer and longer multiple scattering paths through the sample. Click on the picture for more.

Research highlights

Oct 2008: Anderson Localization of Sound observed in three dimensions!

Aluminum bead sample
As reported in Nature Physics, our systematic study of the propagation of ultrasound through a random network of aluminium beads provides the first unambiguous demonstration of the Anderson localization of classical waves in a 3D system. Click here to find out more...

Read our article on the Nature Physics website:
"Localization of ultrasound in a three-dimensional elastic network" H. Hu, A. Strybulevych, J.H. Page, S.E. Skipetrov and B.A. van Tiggelen, Nature Physics, 4, 945-948, (2008).
The original submitted version of this article can be found on arXiv:0805.1502

May 2007: What do Mount Merapi and a glass of beer have in common?

Glass of beer
Read our article in Physics Today to find out more...
Multiple scattering in evolving media, by Roel Snieder and John Page, Physics Today, May 2007, pp. 49-55

September 2004: Phononic Crystal Research

Physical Review Focus and the New Scientist highlight our research on focusing and negative refraction of  ultrasound in phononic crystals.

Read our paper here, or go to our publications list.

February 2002: Ultrasonic Tunneling

Phononic crystal
Nature Physics Portal features our research on ultrasound tunneling in phononic crystals.

    For more information on our current research, click here.