The topological response of matter to electromagnetic fields is a highly demanded property in materials design and metrology due to its robustness against noise and decoherence, stimulating recent advances in ultrafast photonics. Embedding topological properties into the enantiosensitive optical response of chiral molecules could therefore enhance the efficiency and robustness of chiral optical discrimination. Here we achieve such a topological embedding by introducing the concept of chiral topological light—a light beam which displays chirality locally, with an azimuthal distribution of its handedness described globally by a topological charge. The topological charge is mapped onto the azimuthal intensity modulation of the non-linear optical response, where enantiosensitivity is encoded into its spatial rotation. The spatial rotation is robust against intensity fluctuations and imperfect local polarization states of the driving field. Our theoretical results show that chiral topological light enables detection of percentage-level enantiomeric excesses in randomly oriented mixtures of chiral molecules, opening a way to new, extremely sensitive and robust chiro-optical spectroscopies with attosecond time resolution.

物质对电磁场的拓扑响应是材料设计和计量学中一个非常需要的特性，因为它具有抗噪声和退相干的鲁棒性，刺激了超快光子学的最新进展。因此，将拓扑特性嵌入到手性分子的对映敏感光学响应中可以提高手性光学鉴别的效率和稳健性。在这里，我们通过引入手性拓扑光的概念来实现这种拓扑嵌入——一种局部显示手性的光束，其旋向分布由拓扑电荷全局描述。拓扑电荷被映射到非线性光学响应的方位角强度调制上，其中对映灵敏度被编码为其空间旋转。空间旋转对驱动场的强度波动和不完美的局部极化状态具有鲁棒性。我们的理论结果表明，手性拓扑光能够检测随机取向的手性分子混合物中的百分比级对映体过量，为具有阿秒时间分辨率的新型、极其灵敏和强大的手环光学光谱开辟了一条道路。