Tunable topological phase transition in the telecommunication wavelength

Recent progress in the Valley Hall insulator has demonstrated a nontrivial topology property due to the distinct valley index in 2D semiconductor systems. In this work, we propose a highly tunable topological phase transition based on valley photonic crystals. The topological phase transition is realized by the inversion symmetry broken due to the refractive index change of structures consisting of optical phase change material (OPCM) with thermal excitation of different sites in a honeycomb lattice structure. Besides, simulations of light propagation at sharp corners and pseudo-spin photon coupling are conducted to quantitatively examine the topological protection. Compared with other electro-optical materials based on reconfigurable topological photonics, a wider bandwidth and greater tunability of both central bandgap frequency and topological phase transition can happen in the proposed scheme. Our platform has great potential in practical applications in lasing, light sensing, and high-contrast tunable optical filters.& COPY; 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Recent progress in the Valley Hall insulator has shown nontrivial topology due to distinct valley index in 2D semiconductor systems. This study proposes a highly tunable topological phase transition using valley photonic crystals, achieved by breaking the inversion symmetry through refractive index changes in optical phase change material (OPCM) in a honeycomb lattice structure. Simulations demonstrate topological protection through light propagation at sharp corners and pseudo-spin photon coupling. Compared to other reconfigurable topological photonics, the proposed scheme offers wider bandwidth and greater tunability in both central bandgap frequency and topological phase transition. The platform holds great potential for practical applications in lasing, light sensing, and high-contrast tunable optical filters.