AI 中文总结
研究针对过冷分子液体和玻璃中分子动力学探测难题，结合多种技术定制DDLS装置，能捕捉超20个数量级旋转动力学，构建超宽带数据集，实现无时间平均的时间分辨测量，为相关研究建立统一实验框架。
AI 中文摘要
动态光散射（DLS）是探测软凝聚态微观动力学的通用技术。但将DLS应用于过冷分子液体和玻璃时，因去偏振散射弱、玻璃化转变附近弛豫慢及需与互补光谱技术定量比较，对实验性能要求高。本教程讨论如何定制去偏振动态光散射（DDLS）装置应对这些挑战。通过结合传统光纤光子相关光谱和多散斑光子相关成像与高频DDLS，该装置能捕捉超20个数量级的旋转动力学。详细介绍了高信噪比和长期光学稳定性所需的实验设计，以及相干和部分外差效应的处理。经适当处理，不同检测方案产生相同电场自相关函数，可构建连续超宽带DDLS数据集。多散斑检测实现无时间平均的时间分辨相关测量，将DDLS扩展到非平衡系统。此方法为在极宽时间范围内定量研究平衡和非平衡分子重取向动力学建立了统一实验框架。
英文摘要
Dynamic light scattering (DLS) is a versatile technique for probing microscopic dynamics in soft condensed matter. However, applying DLS to supercooled molecular liquids and glasses demands exceptional experimental performance due to weak depolarized scattering, slow relaxation near the glass transition, and the need for quantitative comparison with complementary spectroscopic techniques. In this tutorial we discuss, how a depolarized dynamic light scattering (DDLS) setup can be tailored to meet these challenges. By combining conventional fiber-optical photon correlation spectroscopy, and multispeckle photon correlation imaging with high-frequency DDLS, such a setup allows to capture rotational dynamics across more than 20 orders of magnitude in time. We detail the experimental design required for high signal-to-noise ratios and long-term optical stability, alongside the treatment of coherence and partial heterodyning effects. As we demonstrate, after proper treatment the different detection schemes yield the same electric-field autocorrelation function, enabling the construction of continuous, ultra-broadband DDLS datasets. Furthermore, multispeckle detection enables time-resolved correlation measurements without temporal averaging, extending DDLS to non-equilibrium systems such as aging molecular glasses. This methodology establishes a unified experimental framework for quantitative investigations of equilibrium and non-equilibrium molecular reorientation dynamics over an exceptionally broad time range.
