2016/07/21 by Philipp del Hougne, Fabrice Lemoult, Mathias Fink +1 · 1 citation
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Front (military) #Meteorology #Microwave #Microwave Imaging and Scattering Analysis #Microwave cavity #Optics #Physics #Quantum mechanics #Random lasers and scattering media #Underwater Acoustics Research #physics.class-ph
paper · pdf · doi:10.1103/physrevlett.117.134302
published as Phys. Rev. Lett. 117, 134302 (2016) · 12 pages, 4 figures
arxiv created 2016/07/21 · openalex publication_date 2016/09/22 · arxiv updated 2016/09/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Controlling waves in complex media has become a major topic of interest, notably through the concepts of time reversal and wave front shaping. Recently, it was shown that spatial light modulators can counterintuitively focus waves both in space and time through multiple scattering media when illuminated with optical pulses. In this Letter, we transpose the concept to a microwave cavity using flat arrays of electronically tunable resonators. We prove that maximizing the Green's function between two antennas at a chosen time yields diffraction limited spatiotemporal focusing. Then, changing the photons' dwell time inside the cavity, we modify the relative distribution of the spatial and temporal degrees of freedom (DOF), and we demonstrate that it has no impact on the field enhancement: wave front shaping makes use of all available DOF, irrespective of their spatial or temporal nature. Our results prove that wave front shaping using simple electronically reconfigurable arrays of reflectors is a viable approach to the spatiotemporal control of microwaves, with potential applications in medical imaging, therapy, telecommunications, radar, or sensing. They also offer new fundamental insights regarding the coupling of spatial and temporal DOF in complex media.