# Cooperative light scattering from helical-phase-imprinted atomic rings. (arXiv:1801.00559v1 [quant-ph])

We theoretically investigate the light scattering of the super- and
subradiant states which can be prepared by the excitation of a single photon
which carries an orbital angular momentum (OAM).\ With this helical phase
imprinted on the stacked ring of atomic arrays, the subradiant modes show
directional side scattering in the far-field, allowing for light collimation
and quantum storage of light with OAM.\ For the excitations with linear
polarizations, we find a discrete $C_4$ rotational symmetry in scattering for
the number of atoms $N$ $=$ $4n$ with integers $n$, while for circular
polarizations with arbitrary $N$, the azimuthal and $C_N$ symmetries emerge for