We present an alternative approach for spatiotemporal focusing through complex scattering media by wave front shaping. Using a nonlinear feedback signal to shape the incident pulsed wave front, we show that the limit of a spatiotemporal matched filter can be achieved; i.e., the wave amplitude at the intended time and focus position is maximized for a given input energy. It is exactly what is also achieved with time reversal. Demonstrated with ultrasound experiments, our method is generally applicable to all types of waves.

Phys. Rev. E

Aulbach, J., Bretagne, A., Fink, M., Tanter, M., & Tourin, A. (2012). Optimal spatiotemporal focusing through complex scattering media. Phys. Rev. E, 85(Article number: 16605), 1–7. doi:10.1103/PhysRevE.85.016605