Photonic topological phase transition induced by material phase transition

Abstract

Photonic topological insulators (PTIs) have been proposed as an analogy to topological insulators in electronic systems. In particular, two-dimensional PTIs have gained attention for the integrated circuit applications. However, controlling the topological phase after fabrication is difficult because the photonic topology requires the built-in specific structures. This study experimentally demonstrates the band inversion in two-dimensional PTI induced by the phase transition of deliberately-designed nanopatterns of a phase-change material, Ge2Sb2Te5 (GST), which indicates the first observation of the photonic topological phase transition with changes in the Chern number. This approach allows us to directly alter the topological invariants, which is achieved by symmetry-breaking perturbation through GST nanopatterns with different symmetry from original PTI. The success of our scheme is attributed to the ultrafine lithographic alignment technologies of GST nanopatterns. These results demonstrate to control photonic topological properties in a reconfigurable manner, providing an insight into new possibilities for reconfigurable photonic processing circuits.

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Cited by in corpus (4)

• Tunable Nanophotonic Devices and Cavities based on a Two-Dimensional Magnet
• Topological Lasing from Thouless Pumping in Bilayer Photonic Crystal
• EP restoration and fast-light edge states in photonic crystal waveguide with glide and time reversal symmetry
• Observation of non-Hermitian point gap in photonic crystals