Recent advances in topological photonics have opened up a new paradigm for robust light manipulation. Exploring dynamic control of topological photonic states is one of the key issues in this field, offering significant potential for both fundamental and applied research. Here we propose a scheme to realize tunable valley-topological plasma photonic crystals using bistable kagome superlattices in dielectric barrier discharge. We observe three types of bistable kagome superlattices (types ${\mathrm{I}}_{\pm }, \mathrm{I}{\mathrm{I}}_{\pm }$, and $\mathrm{II}{\mathrm{I}}_{\pm }$), corresponding respectively to zero, radial, and tangential displacements of the cross-point filaments. High-speed imaging reveals that these superlattices comprise three distinct sublattices, in which the spatial displacements occur within the first sublattice, while the other two undergo a ${60}^{\circ }$ rotation for the ± states. By switching the discharge on and off, we demonstrate reversible switching between a conventional dielectric photonic crystal and a plasma-based topological photonic crystal. Moreover, a dynamical control on the frequency of valley-topological edge states is achieved. Our method provides a promising route for generating tunable topological photonic states with the advantages of fast response, low cost, and wide adaptability. It paves the way for many topological applications, including the integrated photonics, signal processing, and controllable optical isolators.

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• Photonic crystals
• Plasma discharges
• Topological insulators
• Valley degrees of freedom
• Low-temperature plasma
• Plasma crystals