Our research group is dedicated to the exploration of novel topological phases and their applications in gyromagnetic photonic crystals. We aim to uncover fundamental insights into topological phenomena within photonic systems, leveraging our findings to innovate in areas such as photonic devices and materials. Below are some of our key research achievements:
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Three-Dimensional Photonic Chern Insulator: We successfully implemented three-dimensional photonic Chern insulators using magnetically tunable photonic crystals. Our work revealed that the isofrequency contours formed by topological surface states exhibit torus knots or links, characterized by integers determined by the Chern vectors. Notably, we established the Chern vector as an intrinsic bulk topological invariant, demonstrating a sample with surface states forming a (2, 2) torus link. This research provides unique topological characteristics to surface states, as published in Nature.
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Non-Hermitian Photonic Chern Insulator: Our experimental investigations into lossy quantum Hall systems revealed that chiral edge states can be localized in a gyromagnetic photonic crystal. By structuring the loss configuration, we achieved a complex energy spectrum with point-gap winding, an intrinsically non-Hermitian topological invariant. This interplay between the Chern number and point-gap winding leads to a robust non-Hermitian skin effect, enhancing the resilience of skin modes against defects and disorders, as detailed in Physical Review Letters.
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Photonic Topological Anderson Insulator: We proposed and experimentally demonstrated a photonic topological Anderson insulator within a disordered gyromagnetic photonic crystal. This work directly observed the disorder-induced topological phase transition from a trivial insulator to a topological Anderson insulator, showcasing robust chiral edge states. Our findings have been recognized as an Editors’ Suggestion and featured in Physics by Physical Review Letters.
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Unpaired Photonic Dirac Point: In a planar two-dimensional gyromagnetic photonic crystal, we observed an unpaired Dirac point, analogous to the Haldane model. By breaking time-reversal symmetry with gyromagnetic materials, we fine-tuned a parity-breaking parameter to achieve this breakthrough, which holds promise for applications in valley filters and angular selective photonic devices, as reported in Nature Communications.
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Photonic Antichiral Boundary States: We reported the discovery of antichiral edge states in a two-dimensional photonic Dirac semimetal and antichiral surface states in a three-dimensional Weyl semimetal. These findings enhance our understanding of topological boundary states and present new opportunities for practical applications, such as topological coaxial cables, as published in Physical Review Letters and Nature Communications.
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Photonic Amorphous Topological Insulators: Our research also delves into the behavior of Chern number-based photonic topological insulators in amorphous phases of matter. By tuning disorder strength, we demonstrated that photonic topological edge states can persist into the amorphous regime prior to the glass-to-liquid transition. This work illuminates the relationship between topology and short-range order in amorphous lattices, paving the way for new classes of non-crystalline topological photonic bandgap materials, as explored in Light Science & Applications.
Through these pioneering studies, our group aims to advance the understanding of topological phenomena in photonic systems and to develop innovative applications that leverage these unique properties.