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As one of important optical properties of chiral molecules, the real-time monitoring of the optical rotation is of great significance to study the reaction characteristics of chiral molecules. In this study, we have built an optical frequency domain weak measurement system with linear common-path method for chiral sensing, in which the response between optical rotation and central wavelength shift can reach more than 1200 nm/rad. The high-precision measurement of the optical rotation of chiral molecules and the high-sensitivity real-time monitoring of the decomposition rate in the acidic hydrolysis of sucrose under different concentrations of catalysts are realized using this system. The experimental results are basically consistent with the theoretical prediction. This study shows that optical weak measurement chiral sensing can monitor the hydrolysis degree of chiral molecules in real time without separating and labeling molecules. It has great application potential in the production and research of chiral compounds, especially chiral medicine. [ABSTRACT FROM AUTHOR]

In this paper, we propose an improved Kalman filtering algorithm, to solve problems associated with processing of direct current (DC) signals in optical current transformers (OCTs). The algorithm was realized as follows. Based on the characteristics of the OCT, mixed noise was included with the parameters and state information of the measurement model, to ensure that it could be processed. State predictions and update equations for the improved Kalman algorithm were obtained, according to the minimum mean squared error criterion, using the established model. Finally, real-time noise estimation and correction was achieved by designing a recursive noise filter. Results from simulations and experiments demonstrate that the improved signal processing algorithm is effective in filtering mixed noise from DC signals measured by an OCT. Furthermore, the proposed algorithm is able to achieve real-time noise correction during the filtering process. [ABSTRACT FROM AUTHOR]