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Photonic topological phase transition induced by material phase transition
Takahiro Uemura1,2, Yuto Moritake1, Taiki Yoda1,2
1Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8550, Tokyo, Japan.
Science Advances
|August 23, 2024
Summary
Researchers demonstrate reconfigurable photonic topological phase transitions in 2D photonic topological insulators (PTIs). This breakthrough uses phase-change material nanopatterns to control topological invariants, paving the way for advanced photonic circuits.
Area of Science:
- Photonics
- Condensed Matter Physics
- Materials Science
Background:
- Photonic topological insulators (PTIs) are analogs to electronic topological insulators with potential in integrated circuits.
- Current PTIs lack control over topological phases post-fabrication due to fixed structures.
Purpose of the Study:
- To experimentally demonstrate a controllable photonic topological phase transition in 2D PTIs.
- To achieve reconfigurable control of topological invariants using phase-change materials.
Main Methods:
- Designed and fabricated nanopatterns of the phase-change material Ge2Sb2Te5 (GST).
- Utilized ultrafine lithographic alignment to integrate GST nanopatterns into a 2D PTI.
- Induced band inversion and topological phase transitions via GST material phase changes.
Main Results:
- Observed the first photonic topological phase transition in a 2D PTI by altering the Chern number.
- Demonstrated reconfigurable control of topological properties through symmetry-breaking GST nanopatterns.
- Successfully altered topological invariants by changing the symmetry of the GST nanopatterns.
Conclusions:
- The study presents a novel method for controlling photonic topological properties in a reconfigurable manner.
- This approach enables dynamic manipulation of topological invariants, crucial for reconfigurable photonic processing circuits.
- Highlights the potential of phase-change materials and advanced lithography for next-generation photonic devices.
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