  Directional emission of photons with designed polarizations and orbital
angular momenta is crucial for exploiting full potential of quantum emitters
(QEs) within quantum information technologies. Capitalizing on the concept of
hybrid plasmon-QE coupled metasurfaces, we develop a holography-based design
approach allowing one to construct surface nanostructures for outcoupling
QE-excited circularly diverging surface plasmon polaritons (SPPs) into
well-collimated beams of photons with desirable polarization characteristics
propagating along given directions. Using the well-established simulation
framework, we demonstrate the efficiency and versatility of the developed
approach by analyzing different hybrid SPP-QE coupled metasurfaces designed for
generation of linearly, radially and circularly polarized photons propagating
in various off-axis directions. Our work enables the design of single-photon
sources with radiation channels that have distinct directional and polarization
characteristics, extending thereby possibilities for designing complex photonic
systems for quantum information processing. Moreover, we believe that the
developed scattering holography approach is generally useful when employing
surface electromagnetic excitations, including SPP modes, as reference waves
for signal wave reconstruction.
