AI 中文总结
研究通过瞬态对称性破缺实现硅超表面中手性的超快全光控制，利用光子本征态对对称性扰动的敏感性，光激发产生自由载流子打破对称，实现手性可逆调控，为相关技术发展开辟道路。
AI 中文摘要
手性支撑着广泛的光与物质相互作用，但光子系统中其动态控制方法仍然有限。在此，我们通过瞬态对称性破缺展示了硅超表面中手性的超快全光控制。我们的方法利用了具有相反空间宇称的光子本征态，其对对称性扰动高度敏感。光激发产生自由载流子，在膜厚度上建立瞬态折射率梯度，打破面外镜面对称性，促进宇称相反模式杂化到手性光子态。这能在10 - 100皮秒时间尺度上可逆地产生和调制手性，表现为超表面圆二色性的显著变化。通过动态重新配置光子结构的基本对称性质而非仅仅其光学响应，我们的工作为超快控制手性光与物质相互作用建立了一条途径，并为有源纳米光子和信息处理技术带来了机会。
英文摘要
Chirality underpins a wide range of light-matter interactions, yet methods for its dynamic control in photonic systems remain limited. Here, we demonstrate ultrafast all-optical control of chirality in silicon metasurfaces through transient symmetry breaking. Our approach exploits photonic eigenstates of opposite spatial parity engineered to be highly susceptible to symmetry perturbations. Optical excitation generates free carriers that establish a transient refractive-index gradient across the membrane thickness, breaking out-of-plane mirror symmetry and facilitating hybridization of the parity-opposite modes into chiral photonic states. This enables the reversible creation and modulation of chirality on a 10-100 ps timescale, manifested by pronounced changes in the metasurface circular dichroism. By dynamically reconfiguring a fundamental symmetry property of the photonic structure rather than merely its optical response, our work establishes a route towards ultrafast control of chiral light-matter interactions and opens opportunities for active nanophotonic and information processing technologies.
