衍射极限之上的简并高阶混合连续谱束缚态
Degenerate high-order hybrid bound states in the continuum beyond diffraction limit
AI总结：
该研究在具有C₆ᵥ对称性的周期光子结构中，于衍射极限之上，通过结合对称性保护、二次带简并与参数调谐，实现了具有高阶拓扑电荷的简并混合连续谱束缚态（BICs），揭示了其新机制并为相关领域开辟了机遇。
AI中文摘要：
我们在具有C₆ᵥ对称性的周期光子结构中，于衍射极限之上，证明了存在具有高阶拓扑电荷和二次简并的Γ点处简并混合连续谱束缚态（BICs）。该简并BICs通过结合对称性保护（其抑制辐射进入零级衍射通道）、二次带简并以及参数调谐以消除辐射进入一级衍射通道来实现。利用有效哈密顿量研究简并点附近的带结构，并表征所有衍射通道中的拓扑动力学。本工作揭示了一种在衍射极限之上实现简并BICs的新机制，为新物理及应用开辟了机遇。
英文摘要：
We demonstrate the existence of at-$Γ$ degenerate hybrid bound-states in the continuum (BICs) with high-order topological charges and quadratic band degeneracy in periodic photonic structures with $C_{6v}$ symmetry above the diffraction limit. The degenerate BICs are realized by combining symmetry protection, which suppresses radiation into zeroth-order diffraction channel, with quadratic band degeneracy and parameter tuning to eliminate radiation into first-order diffraction channels. An effective Hamiltonian is used to investigate the band structure around the degeneracy point, and the topological dynamics in all diffraction channels are characterized. This work reveals a novel mechanism for realizing degenerate BICs above the diffraction limit, opening up opportunities for new physics and applications.
