基于数字全息术的光学活性及圆二色性分布动态测量方法研究

作为手性物质的重要光学性质，光学活性和圆二色性可以提供丰富的手性样品内部信息，在生物医学、化学、制药、材料科学等领域发挥着重要作用。然而，较弱的手性信号导致传统检测方法的信噪比较低，并且目前尚无有效方法能够对手性样品光学活性及圆二色性二维分布进行同时动态测量。为此，拟通过借助数字全息术实时获取被手性样品调制的物光波复振幅及偏振分布，实现对两种手性参量的同时高精度动态测量。主要研究内容：不同偏振态物光波数字全息术测量手性参量的物理机制；手性测量方案的实验实现及测量信噪比的提高途径。可能的创新点：提出将数字全息术应用于手性物质的表征和检测，解决了样品两种手性参量二维分布的同时动态测量问题；提出通过增强光-手性物质相互作用的途径放大被测信号、采用共路干涉结构提高系统测量稳定性，可有效提高手性参量的测量灵敏度。项目的完成有望为手性样品相关物性及变化的研究，提供一种高信噪比的动态实验测试与表征手段。

Optical activity (OA) and circular dichroism (CD), two important optical properties of chiral objects, can provide rich internal information of chiral samples, playing significant roles in biomedical, chemistry, pharmaceutical and material sciences. However, the signal-to-noise ratio (SNR) of conventional chiral detection methods is low due to the weak chiroptical signal. Moreover, no available method has been developed to dynamically measure the OA and CD distributions of chiral samples simultaneously nowadays. For this purpose, we propose to realize the simultaneous measurement of OA and CD distributions of chiral samples in real-time with high precision by measuring the complex amplitude and polarization distributions of light waves modulated by chiral samples with the help of digital holography. The main research contents of this project include the physical mechanism of measuring chiral parameters using digital holography with object waves of different polarization states, the experimental realization of chirality measurement and the strategies to improve the measurement SNR. The potential novelty of this project may lie in that digital holography has been proposed to characterize and test chiral matters which can solve the scientific problem of simultaneously measuring OA and CD distributions of chiral samples in real-time. Another potential novelty is we have proposed the strategies of enhancing the chiral light-matter interaction to boost the chiroptical signal and designed common-path interferometry to improve the temporal stability of the measurement system. These can effectively improve the measurement sensitivity for chiral parameters. In a word, the accomplishment of this project will provide a dynamic measurement and characterization tool with high SNR for the physical properties as well as their variations of chiral samples.