Many chiroptical spectroscopic techniques have been developed to detect chirality in molecular species and probe its role in biological processes. Raman optical activity (ROA) should be one of the most powerful methods, as ROA yields vibrational and chirality information simultaneously and can measure analytes in aqueous and biologically relevant solvents. However, despite its promise, the use of ROA has been limited, largely due to challenges in instrumentation. Here, we report a new approach to ROA that exploits high-frequency polarization modulation. High-frequency polarization modulation, usually implemented with a photoelastic modulator (PEM), has long been the standard technique in other chiroptical spectroscopies. Unfortunately, the need for simultaneous spectral and polarization resolution has precluded the use of PEMs in ROA instruments. We combine a specialized camera system (the Zurich imaging polarimeter, or ZIMPOL) with PEM modulation to perform ROA measurements. We demonstrate performance similar to the current standard in ROA instrumentation while reducing complexity and polarization artifacts. This development should aid researchers in exploiting the full potential of ROA for chemical and biological analysis.

中文翻译：

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用高频偏振调制测量拉曼光学活动

已经开发了许多手性光谱技术来检测分子物种中的手性并探测其在生物过程中的作用。拉曼光学活性 (ROA) 应该是最强大的方法之一，因为 ROA 同时产生振动和手性信息，并且可以测量水性和生物相关溶剂中的分析物。然而，尽管有希望，但 ROA 的使用受到限制，这主要是由于仪器方面的挑战。在这里，我们报告了一种利用高频极化调制的 ROA 新方法。高频偏振调制，通常用光弹性调制器 (PEM) 实现，长期以来一直是其他手性光谱学的标准技术。不幸的是，同时光谱和偏振分辨率的需要排除了在 ROA 仪器中使用 PEM。我们将专门的相机系统（苏黎世成像偏振计，或 ZIMPOL）与 PEM 调制相结合来执行 ROA 测量。我们展示了类似于 ROA 仪器中当前标准的性能，同时降低了复杂性和极化伪影。这一发展应该有助于研究人员充分利用 ROA 进行化学和生物分析的潜力。