Manipulating spatiotemporal degrees of freedom of waves in random media

Phys Rev Lett. 2009 Oct 23;103(17):173902. doi: 10.1103/PhysRevLett.103.173902. Epub 2009 Oct 20.

Abstract

We show that all the spatiotemporal degrees of freedom available in a complex medium can be harnessed and converted into spatial ones. This is demonstrated experimentally through an instantaneous spatial inversion, using broadband ultrasonic waves in a multiple scattering sample. We show theoretically that the inversion convergence is governed by the total number of degrees of freedom available in the medium for a fixed bandwidth and demonstrate experimentally its use for complex media investigation. We believe our approach has potential in sensing, imagery, focusing, and telecommunication.