Guan Tingting, Wang Zhenyu, Wang Ruize, Wu Zihan, Wang Chaowei, Wu Dong, Chu Jiaru, Chen Yang
Chinese Academy of Sciences Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, 230027 Hefei, China.
Nanophotonics. 2025 Jan 17;14(8):1083-1089. doi: 10.1515/nanoph-2024-0620. eCollection 2025 Apr.
Circular dichroism (CD) spectroscopy is essential for biochemistry, structural biology and pharmaceutical chemistry. While the chiroptical properties of chiral molecules are characterized by the Pasteur parameter , it is commonly conceived that the generation of CD is solely attributed to the imaginary part ''. However, since the imaginary part '' is orders of magnitude smaller than the real part ' for most chiral molecules, the achievable sensitivity of CD spectroscopy is quite limited. Here, we report a recipe for realizing ultrasensitive CD spectroscopy based on the ' component of chiral molecules. Two quasi-bound states in the continuum are coupled by chiral molecules to form two hybridized branches, whose wavelengths and eigenpolarizations are very sensitive to the value of '. Giant CD signals over four orders of magnitude larger than the case without mode coupling are thus produced, paving the way towards chiral structure analysis at the single molecule level.
圆二色光谱（CD）对于生物化学、结构生物学和药物化学至关重要。虽然手性分子的旋光性质由巴斯德参数表征，但通常认为CD的产生仅归因于虚部。然而，由于对于大多数手性分子而言，虚部比实部小几个数量级，因此CD光谱可实现的灵敏度相当有限。在此，我们报告了一种基于手性分子实部实现超灵敏CD光谱的方法。连续统中的两个准束缚态通过手性分子耦合形成两个杂化分支，其波长和本征极化对手性分子实部的值非常敏感。由此产生了比无模式耦合情况下大四 个数量级以上的巨大CD信号，为单分子水平的手性结构分析铺平了道路。
