The recent development in topological photonics has revealed a variety of exotic phenomena such as Weyl degeneracy. However, a Weyl nodal surface, a two-dimensional topological degeneracy, has not been reported in Hermitian photonics. In this paper, topologically nontrivial photonic nodal surface in a helix structure possessing twofold screw symmetry and time-reversal symmetry is demonstrated. In contrast to nodal surfaces in other wave systems in which topological phase depends on the system parameters such as coupling strength, nontrivial topological properties of nodal surface in our work are guaranteed by effective photonic properties. Calculated Chern number, Berry curvature, and photonic Fermi arcs support the existence of nontrivial topological phase of the nodal surface. This work suggests the possibilities of many intriguing photonic topological features with nonzero dimensions.

• Received 8 January 2019
• Revised 6 June 2019

DOI:https://doi.org/10.1103/PhysRevB.99.235423