  Optical skyrmions, the optical analogue of topological configurations formed
by three-dimensional vector fields covering the whole 4{\pi} solid angle but
confined in a two-dimensional (2D) domain, have recently attracted growing
interest due to their potential applications in high-density data transfer,
storage, and processing. While the optical skyrmions have been successfully
demonstrated using different field vectors in both of free-space propagating
and near-field evanescent electromagnetic fields, the study on generation and
control of the optical skyrmions, and their general correlation with the
electromagnetic (EM) fields, are still in infancy. Here, we theoretically
propose that an evanescent transverse-magnetic-polarized (TM-polarized) EM
fields with rotational symmetry are actually N\'eel-type optical skyrmions of
the electric field vectors. Such optical skyrmions maintain the rotation
symmetry that are independent on the operation frequency and medium. Our
proposal was verified by numerical simulations and real-space nano-imaging
experiments performed on a graphene monolayer. Such a discovery can therefore
not only further our understanding on the formation mechanisms of EM
topological textures, but also provide a guideline for facile construction of
EM skyrmions that may impact future information technologies.
