Observation of $\pi$ solitons in oscillating waveguide arrays

Abstract

Floquet systems with periodically varying in time parameters enable realization of unconventional topological phases that do not exist in static systems with constant parameters and that are frequently accompanied by appearance of novel types of the topological states. Among such Floquet systems are the Su-Schrieffer-Heeger lattices with periodically-modulated couplings that can support at their edges anomalous $\pi$ modes of topological origin despite the fact that the lattice spends only half of the evolution period in topologically nontrivial phase, while during other half-period it is topologically trivial. Here, using Su-Schrieffer-Heeger arrays composed from periodically oscillating waveguides inscribed in transparent nonlinear optical medium, we report experimental observation of photonic anomalous $\pi$ modes residing at the edge or in the corner of the one- or two-dimensional arrays, respectively, and demonstrate a new class of topological $\pi$ solitons bifurcating from such modes in the topological gap of the Floquet spectrum at high powers. $\pi$ solitons reported here are strongly oscillating nonlinear Floquet states exactly reproducing their profiles after each longitudinal period of the structure. They can be dynamically stable in both one- and two-dimensional oscillating waveguide arrays, the latter ones representing the first realization of the Floquet photonic higher-order topological insulator, while localization properties of such $\pi$ solitons are determined by their power.

10 pages, 6 figures, to appear in Science Bulletin

References in corpus (17)

• Topological Photonics
• Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
• Scheme to Achieve Silicon Topological Photonics
• Topological characterization of periodically-driven quantum systems
• Photonic crystal nanocavity based on a topological corner state
• Topologically Robust Transport of Photons in a Synthetic Gauge Field
• Active topological photonics
• Low-threshold topological nanolasers based on second-order corner state
• Chiral symmetry and bulk--boundary correspondence in periodically driven one-dimensional systems
• The creation of two-dimensional composite solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates in free space
• Quantized Nonlinear Thouless Pumping
• Cavity Quantum Electrodynamics with Second-Order Topological Corner State
• Observation of edge solitons in topological trimer arrays
• Bimorphic Floquet Topological Insulators
• Tight-binding methods for general longitudinally driven photonic lattices -- edge states and solitons
• Weakly nonlinear topological gap solitons in Su-Schrieffer-Heeger photonic lattices
• Two-dimensional nonlinear Thouless pumping of matter waves

Cited by in corpus (4)

• $\pi$ mode lasing in the non-Hermitian Floquet topological system
• Topological edge states in photonic Floquet insulator with unpaired Dirac cones
• Two-dimensional flat-band solitons in superhoneycomb lattices
• Floquet valley Hall edge solitons