Precise Localization of Multiple Noncooperative Objects in a Disordered Cavity by Wave Front Shaping

Philipp Del Hougne, Mohammadreza F. Imani, Mathias Fink, David R. Smith, Geoffroy Lerosey

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Complicated multipath trajectories of waves in disordered cavities cause object localization to be very challenging with traditional ray-tracing approaches. Yet it is known that information about the object position is encoded in the Green's function. After a calibration step, traditional time-reversal approaches retrieve a source's location from a broadband impulse response measurement. Here, we show that a nonemitting object's scattering contribution to a reverberant medium suffices to localize the object. We demonstrate our finding in the microwave domain. Then, we further simplify the scheme by replacing the temporal degrees of freedom (d.o.f.) of the broadband measurement with spatial d.o.f. obtained from wave front shaping. A simple electronically reconfigurable reflectarray inside the cavity dynamically modulates parts of the cavity boundaries, thereby providing spatial d.o.f. The demonstrated ability to localize multiple noncooperative objects with a single-frequency scheme may have important applications for sensors in smart homes.

Original languageEnglish (US)
Article number063901
JournalPhysical Review Letters
Issue number6
StatePublished - Aug 6 2018
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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