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Dynamically reconfigurable topological edge state in phase change photonic crystals
Tun Cao1, Linhan Fang1, Ying Cao1
1School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China.
Science Bulletin
|January 20, 2023
Summary
Researchers developed a novel topological photonic crystal using a phase-change material. This allows for reversible switching of topological edge states (TESs), enabling tunable photonic devices and scatter-free light propagation.
Area of Science:
- Photonics
- Condensed Matter Physics
- Materials Science
Background:
- Topological edge states (TESs) offer robust wave propagation, overcoming scattering from imperfections.
- Topological photonic crystals (PhCs) enable one-way propagation of TESs with advantages like lossless transmission and high fabrication tolerance.
Purpose of the Study:
- To address the limitation of non-reversible switching in existing TESs.
- To propose and demonstrate a tunable topological PhC using a phase-change material for dynamic control of TESs.
Main Methods:
- Utilized Ge2Sb2Te5 (GST225), a phase-change material, within a topological PhC design.
- Investigated the reversible switching of TESs by transitioning GST225 between amorphous and crystalline states.
- Analyzed the maintenance of PhC topology by tuning refractive index rather than geometry.
Main Results:
- Achieved reversible switching of TESs 'on' and 'off' by altering GST225's structural state.
- Demonstrated continuous tuning of the photonic bandgap and TES spectral position via gradual GST225 crystallization.
- Confirmed that GST225 phase transitions can be engineered within nanoseconds.
Conclusions:
- The proposed GST225-based topological PhC offers a platform for dynamically tuning TESs.
- This technology has potential applications in tunable photonic devices, topological optical circuits, and scatter-free light propagation.
