Emerging applications of metasurfaces in classical and quantum optics are driving the need for precise polarization control of nearly-degenerate, high quality (Q)-factor modes. However, current approaches to creating specifically polarized pairs of modes force a trade-off between maintaining high Q factors and robustness. Here, we solve this challenge by employing pairwise generation, annihilation, and positioning of polarization singularities, derived from symmetry-guaranteed pairs of symmetry-protected bound states in the continuum. We experimentally demonstrate this design paradigm in silicon metasurfaces with mode splittings of ≈20  nm, mode splitting deviations as low as 1 nm, and Q factors up to 200. This approach opens new avenues for enhancing metasurface performance across a diverse range of applications, including sensing, modulating, nonlinear mixing, and generating quantum light.

中文翻译：

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超表面中偏振奇点成对定位的双频偏振控制。


超表面在经典光学和量子光学中的新兴应用推动了对近乎简并的高质量 （Q） 因子模式的精确偏振控制的需求。然而，目前创建特定极化模式对的方法迫使在保持高 Q 因子和稳健性之间进行权衡。在这里，我们通过采用偏振奇点的成对生成、湮灭和定位来解决这一挑战，这些奇点源自连续体中对称保证的一对对称保护的束缚态。我们在硅超表面中实验证明了这种设计范式，其模式分裂为 ≈20 nm，模式分裂偏差低至 1 nm，Q 因子高达 200。这种方法为提高各种应用中的超表面性能开辟了新的途径，包括传感、调制、非线性混合和产生量子光。