Designing multi-directional energy-splitters and topological valley supernetworks

TL;DR

This paper introduces a geometric design framework for multi-directional topological valley wave networks, enabling tunable energy splitters and the creation of complex supernetworks for advanced wave manipulation.

Contribution

It presents a novel geometric approach to design multi-directional valley wave splitters and supernetworks, expanding beyond traditional 2-directional devices with tunable directionality.

Findings

Design of interfacial wave networks with 2 to 5 directions

Demonstration of tunable directionality via geometry

First realization of a topological supernetwork

Abstract

Using group theoretic and topological concepts, together with tunneling phenomena, we geometrically design interfacial wave networks that contain splitters which partition energy in 2, 3, 4 or 5 directions. This enriches the valleytronics literature that has, so far, been limited to 2-directional splitters. Additionally, we describe a design paradigm that gives greater detail, about the relative transmission along outgoing leads, away from a junction; previously only the negligible transmission leads were predictable. We utilise semi-analytic numerical simulations, as opposed to finite element methods, to clearly illustrate all of these features with highly resolved edge states. As a consequence of this theory, novel networks, with directionality tunable by geometry, ideal for applications such as beam-splitters, switches and filters are created. Coupling these novel networks, that contain multi-directional energy-splitters, culminates in the first realization of a topological supernetwork.