Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatio-temporal wavefront shaping in a microwave cavity   Controlling waves in complex media has become a major topic of interest,
notably through the concepts of time reversal and wavefront shaping. Recently,
it was shown that spatial light modulators can counter-intuitively 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 spatio-temporal 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: wavefront shaping makes use of all available DoF,
irrespective of their spatial or temporal nature. Our results prove that
wavefront shaping using simple electronically reconfigurable arrays of
reflectors is a viable approach to the spatio-temporal 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.

17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga