Recent advances in photonic structures with three-dimensional (3D) Weyl points offer exciting opportunities for exploring nontrivial Fermi arc surface states and enabling novel light-manipulation capabilities. However, previous studies mainly focused on exploring Fermi arc surface states operating in a single frequency band, leading to limited potential applications in multiband topological photonic routing, wave division, switching, and so on. Here, we demonstrate the existence of dual-band topological Fermi arc surface states in the 3D chiral photonic Weyl metamaterials. The dual-band gap mode physics originates from the Weyl points of different frequencies and the time-reversal symmetry is preserved. Through rigorous theoretical analysis, we study the size of the dual-band gaps that vary with the parameter $k_z$ and reveal the Weyl points as the critical points for topological phase transitions. Remarkably, the bandwidth-controllable, highly localized, and unidirectional dual-band Fermi arc surface states appear when the chiral metamaterials are in contact with the vacuum state. Moreover, a type of four-channel reconfigurable and multiband topological photonic routings is demonstrated utilizing the dual-band Fermi arc surface states. We reveal that the physical mechanism of realizing the multichannel reconfigurable topological pathways is caused by the frequency-chirality-locking of the highly localized Fermi arc surface states. Our work could offer insights into 3D Weyl semimetals and provide more flexibility for multiband topological photonic routings.

Close

PrevNext

View figure in article

• Metamaterials
• Photonics
• Surface states
• Topological materials
• Waveguides
• Weyl semimetal