  Nanophotonic chiral antennas exhibit orders of magnitude higher circular
dichroism (CD) compared to molecular systems. Merging magnetism and structural
chirality at the nanometric level allows for the efficient magnetic control of
the dichroic response, bringing exciting new prospects to active nanophotonic
devices and magnetochirality. Here we devise macroscale enantiomeric
magnetophotonic metasurfaces of plasmon and ferromagnetic spiral antennas.
Mixed 2D- and 3D- chiral nanoantennas induce large CD response, where we
identify reciprocal and non-reciprocal contributions. The simultaneous
chiroptical and magneto-optical response in a wide spectral range with these
metasurfaces delivers an attractive platform for the study of magnetochirality
at the nanoscale. Exploring further this type of magnetophotonic metasurfaces
allows the realization of high-sensitivity chiral sensors and prompts the
design of novel macroscopic optical devices operating with polarized light.
