Title: Hybrid Cavity from Tunable Coupling between Anapole and Fabry-Perot Resonance or Anti-resonance Show Chinese title

Title: 可调耦合的安波尔与法布里-珀罗共振或反共振之间的混合腔

Abstract: Enhancing light-matter interactions depends critically on the ability to tailor photonic modes at subwavelength scales, and combining distinct resonant modes has shown remarkable potential unattainable by individual resonances alone. Despite recent advances in anapole metasurfaces for energy confinement and Fabry-Perot (FP) cavities for spectral control, their synergistic coupling and resulting opportunities remain largely unexplored due to challenges such as precise nanoscale assembly. Here, we demonstrate that embedding a terahertz (THz) anapole metasurface within a tunable FP cavity results in a hybrid cavity that demonstrates exotic properties as the anapole transitions between coupling to FP resonances and anti-resonances via cavity-length tuning. At room temperature, we observe ultrastrong coupling (> 30% of the anapole frequency) between anapoles and FP resonances, generating tunable-dispersion polaritons that blend favorable properties of both modes. Meanwhile, anapole spectrally aligns with FP anti-resonances, leading to weak coupling that narrows the linewidth of the anapole's transmission peak by two orders of magnitude and enhances its local density of states (LDOS) near the metasurface correspondingly. With exceptional capabilities including formation of polaritons and significant enhancement of LDOS, the hybrid cavity enables strong interaction with functional materials, paving the way for exploration of quantum optics, molecular sensing, and ultrafast nonlinear photonics. Show Chinese abstract

Abstract: 增强光-物质相互作用的关键在于在亚波长尺度上定制光子模式的能力，结合不同的共振模式展现出个体共振无法实现的显著潜力。 尽管在偶极子禁戒元表面用于能量约束和法布里-珀罗（FP）腔用于光谱控制方面取得了最近的进展，但由于精确纳米级组装等挑战，它们的协同耦合及其带来的机会仍大多未被探索。 在这里，我们证明将太赫兹（THz）偶极子禁戒元表面嵌入可调FP腔中会产生一种混合腔，该腔在通过腔长调节使偶极子在与FP共振和抗共振耦合之间过渡时表现出奇特的特性。 在室温下，我们观察到偶极子与FP共振之间的超强耦合（超过偶极子频率的30%），产生可调色散的极化子，融合了两种模式的优点。 同时，偶极子在光谱上与FP抗共振对齐，导致弱耦合，使偶极子的透射峰线宽缩小两个数量级，并相应地增强了元表面附近的局部态密度（LDOS）。 凭借形成极化子和显著增强LDOS等卓越能力，这种混合腔能够与功能材料产生强相互作用，为量子光学、分子传感和超快非线性光子学的研究铺平了道路。