Experimental demonstration of angular momentum-dependent topological transport using a transmission line network

Nat Commun. 2019 Jan 25;10(1):434. doi: 10.1038/s41467-018-08281-9.

Abstract

Novel classical wave phenomenon analogs of the quantum spin Hall effect are mostly based on the construction of pseudo-spins. Here we show that the non-trivial topology of a system can also be realized using orbital angular momentum through a coupling between the angular momentum and the wave vector. The idea is illustrated with a tight-binding model and experimentally demonstrated with a transmission line network. We show experimentally that even a very small network cluster exhibits angular momentum-dependent one-way topological edge states, and their properties can be described in terms of local Chern numbers. Our work provides a new mechanism to realize counterparts of the quantum spin Hall effect in classical waves and may offer insights for other systems.

Publication types

  • Research Support, Non-U.S. Gov't