2025/07/21 by Liang Zhang, Zirui Zhao, Zhang, Liang +8 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Quantum Mechanics and Non-Hermitian Physics #Quantum optics and atomic interactions #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2507.15309
openalex publication_date 2025/07/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We propose a novel type of topological excitation topological event wavepackets (TEWs) emerging in photonic spacetime crystals (STCs) with spacetime modulated dielectric constants. These TEWs exhibit strong spatiotemporal localization and are topologically protected by a fully opened energy momentum (ωk) gap, within which conventional steady states are absent. We further demonstrate that TEWs are spectrally confined within the ωk-gap, providing a combined measurement for probing the emergence of TEW and the ωk-gap size. Furthermore, we construct a spacetime winding number to elucidate the protection of these events. Unlike previously reported nolinearity-induced event solitons, TEWs originate from topological configuration for linear media, thereby more accessible and versatile for experimental realization. Moreover, we show that TEWs can be periodically woven to form an event lattice, enabling to suppress unwanted noise amplification. Our findings open a new pathway toward topological control in photonic spacetime-modulated systems, enabling the ωk-gap band enginering for wave manipulation ranging from microwave to optical regimes.