Novel topological beam-splitting in photonic crystals

Abstract

We create a passive wave splitter, created purely by geometry, to engineer three-way beam splitting in electromagnetism in transverse electric polarisation. We do so by considering arrangements of Indium Phosphide dielectric pillars in air, in particular we place several inclusions within a cell that is then extended periodically upon a square lattice. Hexagonal lattice structures more commonly used in topological valleytronics but, as we discuss, three-way splitting is only possible using a square, or rectangular, lattice. To achieve splitting and transport around a sharp bend we use accidental, and not symmetry-induced, Dirac cones. Within each cell pillars are either arranged around a triangle or square; we demonstrate the mechanism of splitting and why it does not occur for one of the cases. The theory is developed and full scattering simulations demonstrate the effectiveness of the proposed designs.

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Cited by in corpus (8)

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• Coupled cavity-waveguide system based on topological corner state and edge state
• The Nature of Topological Protection in Spin and Valley Hall Insulators
• Hybrid topological guiding mechanisms for photonic crystal fibers
• Experimental observations of topologically guided water waves within non-hexagonal structures
• Tailored Topological Edge Waves via Chiral Hierarchical Metamaterials
• Tunable three-way valley Hall energy-splitter: venturing beyond graphene-like structures