  A novel approach to improving the performances of confocal scanning imaging
is proposed. We experimentally demonstrate its feasibility using acoustic
waves. It relies on a new way to encode spatial information using the temporal
dimension. By moving an emitter, used to insonify an object, along a circular
path, we create a temporally modulated wavefield. Due to the cylindrical
symmetry of the problem and its temporal periodicity, the spatiotemporal input
field can be decomposed into harmonics corresponding to different spatial
vortices, or topological charges. Acquiring the back-reflected waves with
receivers which are also rotating, multiple images of the same object with
different Point Spread Functions (PSFs) are obtained. Not only is the
resolution improved compared to a standard confocal configuration, but the
accumulation of information also allows building images beating the diffraction
limit. The topological robustness of the approach promises good performances in
real life conditions.
