  The realization of geometric phase optical device operating over a broad
spectral range is usually confronted with intrinsic limitations depending of
the physical process at play. Here we propose to use chiral nematic liquid
crystal slabs with helical ordering that varies in three dimensions. Namely,
gradient-pitch cholesterics endowed with in-plane space-variant angular
positioning of the supramolecular helix. By doing so, we show that the recently
introduced Bragg-Berry mirrors [Opt. Lett. {\bf 41}, 3972-3975 (2016)] can be
endowed with ultra-broadband spectral range. Experimental demonstration is made
in the case of ultra-broadband optical vortex generation in the visible domain.
These results offer practical solution to the polychromatic management of the
orbital angular momentum of light combining the circular Bragg reflection of
chiral media with the Berry phase.
