PT-symmetric phase in kagome photonic lattices

Abstract

Kagome lattice is a two-dimensional network of corner-sharing triangles and is often associated with geometrical frustration. In particular, the frustrated coupling between waveguide modes in a kagome array leads to a dispersionless flat band consisting of spatially localized modes. Here we propose a complex photonic lattice by placing $\mathcal{P}\mathcal{T}$-symmetric dimers at the kagome lattice points. Each dimer corresponds to a pair of strongly coupled waveguides. With balanced arrangement of gain and loss on individual dimers, the system exhibits a $\mathcal{P}\mathcal{T}$-symmetric phase for finite gain/loss parameter up to a critical value. The beam evolution in this complex kagome waveguide array exhibits a novel oscillatory rotation of optical power along the propagation distance. Long-lived local chiral structures originating from the nearly flat bands of the kagome structure are observed when the lattice is subject to a narrow beam excitation.

5 pages, 5 figures

References in corpus (7)

• Nonreciprocal light transmission in parity-time-symmetric whispering-gallery microcavities
• Observation of a localized flat-band state in a photonic Lieb lattice
• Observation of bound states in Lieb photonic lattices
• Topological Insulators and Nematic Phases from Spontaneous Symmetry Breaking in 2D Fermi Systems with a Quadratic Band Crossing
• PT-Symmetric Talbot Effects
• PT-symmetry in optics beyond the paraxial approximation
• Engineering wavefront caustics trajectories in $\mathcal{P}\mathcal{T}$-symmetric lattices

Cited by in corpus (13)

• Artificial flat band systems: from lattice models to experiments
• Dirac magnons in honeycomb ferromagnets
• Localization of weakly disordered flat band states
• Defect states emerging from a non-Hermitian flat band of photonic zero modes
• Flat bands in lattices with non-Hermitian coupling
• Flat-band engineering in tight-binding models: Beyond the nearest-neighbor hopping
• Non-Hermitian lattices with a flat band and polynomial power increase
• Revisiting the optical $PT$-symmetric dimer
• Granular Superconductor in a honeycomb lattice as a realization of Bosonic Dirac Material
• Non-Hermitian flatband generator in one dimension
• Isolated flat bands in 2D lattices based on a novel path-exchange symmetry
• Simulating graphene dynamics in one-dimensional modulated ring array with synthetic dimension
• Exceptional topology in non-Hermitian twisted bilayer graphene