AI 中文总结
研究单个介电亚波长谐振器作为方向选择性高次谐波源，通过米氏模式激发和杂化控制谐波阶次，其结构不对称导致谐波产生的前后不对称，为高次谐波非对称产生提供平台，拓展强场光物质相互作用控制手段。
AI 中文摘要
高次谐波产生（HHG）能产生阿秒光脉冲以及桌面型相干极紫外和软X射线辐射源。长期以来，HHG一直与气体和等离子体相关，而纳米结构固体正成为增强和控制HHG的新替代源。本文通过实验证明并从理论上描述了单个介电亚波长谐振器可作为方向选择性高次谐波源，通过米氏模式的激发和杂化控制多个谐波阶次。该谐振器几何体积为\(0.12 \lambda^3\)，泵浦波长处光学模式体积为\(0.03 \lambda^3\)。沿传播方向的结构不对称导致相反照明方向下不同模式耦合，在第三、五、七次谐波产生中出现明显的前后不对称。这些结果将双各向异性亚波长谐振器确立为灵活非对称产生高次谐波的平台，扩展了利用米氏共振纳米光子学控制强场光物质相互作用的工具箱。
英文摘要
High-harmonic generation (HHG) enables attosecond light pulses and table-top sources of coherent extreme-ultraviolet and soft X-ray radiation. Although HHG has long been associated with gases and plasma, nanostructured solids are emerging as new alternative sources enabling both the enhancement and control of HHG. Here, we experimentally demonstrate and theoretically describe that a single dielectric subwavelength resonator can act as a direction-selective high-harmonic source, enabling control over multiple harmonic orders through the excitation and hybridization of Mie modes. The resonator's geometrical volume is $0.12 λ^3$, and its optical mode volume is $0.03 λ^3$ at its pump wavelength. Structural asymmetry of the resonator along the propagation direction translates into different mode coupling under opposite illumination directions, resulting in pronounced forward-backward asymmetry in the generation of the third, fifth, and seventh harmonics. These results establish bianisotropic subwavelength resonators as a platform for flexible asymmetric generation of high harmonics, expanding the toolbox for controlling strong-field light-matter interactions with Mie-resonant nanophotonics.
