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

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Cited by in corpus (15)

• Observation of nonlinear fractal higher-order topological insulator
• Anomalous topological edge modes in a periodically-driven trimer lattice
• Observation of nonlinear topological corner states originating from different spectral charges
• Topological edge states in photonic Floquet insulator with unpaired Dirac cones
• $\pi$ mode lasing in the non-Hermitian Floquet topological system
• Observation of nonlinear higher-order topological insulators with unconventional boundary truncations
• Floquet valley Hall edge solitons
• Two-dimensional flat-band solitons in superhoneycomb lattices
• Localized Floquet modes in arrays of out-of-phase curved waveguides with a quasiperiodic modulation
• Vortex solitons in disclination quasicrystals
• Quadratic solitons in higher-order topological insulators
• Floquet states on disclinations
• Self-Accelerating Topological Edge States
• Stable vortex soliton arrays in disclination-fractal systems
• Oscillating edge states in polariton topological insulators