Experimental demonstration of non-adjacent band topology connecting multiple nodal links

Abstract

Nodal links are special configurations of band degeneracies in the momentum space, where nodal line branches encircle each other. In PT symmetric systems, nodal lines can be topologically characterized using the eigenvector frame rotations along an encircling loop and the linking structure can be described with non-Abelian frame charges interacting among adjacent bands. In this paper, we present a photonic multiple nodal links system, where non-adjacent band topology is proposed to characterize the hidden relation between nodal lines from non-adjacent band pairs. Through an orthogonal nodal chain, the nodal line from the lower two bands predicts the existence of nodal lines formed between the higher bands. We designed and fabricated a metamaterial, with which the multiple nodal links and non-adjacent band topology are experimentally demonstrated.

References in corpus (6)

• Topological Photonics
• Topological Node-Line Semimetal in Three Dimensional Graphene Networks
• Topological nodal line semimetals
• Topological Euler class as a dynamical observable in optical lattices
• Geometric approach to fragile topology beyond symmetry indicators
• Phase transitions of non-Abelian charged nodal links in a spring-mass system

Cited by in corpus (2)

• Demonstration of non-Abelian frame charge flow in photonic crystals
• Intrinsic triple degeneracy point bounded by nodal surfaces in chiral photonic crystal