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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Fractal polariton topological insulator
Optics Letters
|December 1, 2025
Summary
We demonstrate a novel higher-order polariton topological insulator (HOTI) using fractal geometry. This system enables controllable localization of light modes in fractal corners, opening new possibilities for photonic devices.
Area of Science:
- Condensed Matter Physics
- Photonics
- Topological Materials
Background:
- Higher-order topological insulators (HOTIs) offer unique edge and corner states.
- Fractal geometries present complex structures with potential for novel physical phenomena.
- Polaritonics combines quantum optics and condensed matter physics for light-matter interactions.
Purpose of the Study:
- To realize a higher-order polariton topological insulator (HOTI) in a fractal microcavity system.
- To investigate the localization of light modes in the corners of Sierpiński gasket-like fractal structures.
- To explore nonlinear optical control over these localized modes.
Main Methods:
- Fabrication of microcavity pillars arranged in a fractal (Sierpiński gasket) geometry.
- Utilizing resonant optical pumping to excite nonlinear corner modes.
- Performing linear stability analysis to confirm the dynamical stability of the localized states.
Main Results:
- Demonstrated a fractal HOTI supporting localized modes in external or internal corners based on structural distortion.
- Achieved selective excitation of nonlinear polariton corner modes via optical pumping.
- Observed polariton-polariton interactions leading to resonance curve tilting and bistability, enabling control over mode profiles.
Conclusions:
- Nontrivial topology can manifest in self-similar, aperiodic fractal structures.
- Fractal geometry offers new pathways for light localization in polariton HOTIs.
- Controllable nonlinear corner modes show promise for advanced photonic applications.
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