Angle-driven topological phase transition in 2D photonic crystals: a cavity-waveguide coupled system for EIT-like...

Area of Science:

• Topological photonics
• Metamaterial design
• Electromagnetics

Background:

• Topological photonics offers robust control of light propagation.
• Phase transitions in engineered materials can induce topological changes.
• Coupling different topological states is key to novel photonic functionalities.

Purpose of the Study:

• To design unit cells with phase transitions for topological applications.
• To realize and couple topological edge states (TES), topological corner states (TCS), and trivial cavities (TC).
• To investigate the generation of an electromagnetically induced transparency analogue (EIT-like) effect in a cavity-waveguide coupled system (CWCS).

Main Methods:

• Design of two nontrivial unit cells with phase transition driven by rotation angle.
• Analysis of energy band evolution and calculation of topological indices.
• Realization of TES waveguide, TCS, and TC using topologically distinct unit cells.
• Theoretical calculation and numerical simulation of the CWCS and EIT-like effect.

Main Results:

• Discovery of distinct topological properties in the designed unit cells.
• Successful realization of TES waveguide, TCS, and TC.
• Demonstration of an EIT-like effect through coupling TCS, TC, and TES waveguide in a CWCS.
• Verification of robustness against structural defects and good sensitivity for refractive index sensing.

Conclusions:

• The study successfully demonstrates a novel CWCS for generating an EIT-like effect with topological control.
• The developed system exhibits robustness and sensitivity, suitable for refractive index sensing.
• This work provides a foundation for advanced applications in topological photonics and sensing.