Search

In this study, a method to improve the detection accuracy of a “weak measurement” system of optical rotation was proposed by determining the optimal total phase difference of the system. Analysis of the characteristics of weak measurement regime of the system under different total phase differences provided the total phase difference corresponding to the regime with the smallest ratio of system noise level to sensitivity (that is, the highest system resolution). In this regime, an optical rotation resolution of 5.522 × 10−6° was obtained, which is nearly an order of magnitude higher than the original system.

The traditional method of frequency domain weak measurement has a lot of noise. In this paper, we analyze the 2000 curves obtained by experiments and get the conclusion that the signal-to-noise ratio will increase with the increase of signal strength. We simulated the 252 curves produced by the phase change and used this to fit the relationship between the original calculation method and our spectral height ratio (HR) method. Through previous experimental data verification, our method can greatly reduce the system noise of the dual-mode working area in the frequency domain weak measurement. At present, universal frequency domain weak measurement and measurement system have received increasing attention. In this paper, we introduce a frequency domain weak measurement with spectrum height ratio (HR) that can greatly reduce the system noise in the frequency domain weak measurement bimodal work area. Moreover, we completed comparative experiments on a total internal reflection weak measurement system. The experimental results show that the system resolution obtained by using the HR method is 6.33 × 10-7 RIU, which is an order of magnitude higher than that of the conventional center wavelength offset algorithm which is commonly used in weak frequency measurement.

In the field of electrochemical energy storage systems, the use of in situ detection technology helps to study the mechanism of electrochemical reaction. Our group has previously in situ detected the electrochemical reaction in vanadium flow batteries by total internal reflection (TIR) imaging. In order to further improve the detection resolution, in this study, the weak measurement (WM) method was introduced to in situ detect the electrochemical reaction during the linear sweep voltammetry or the cyclic voltammetry tests with quantitative measurement of the absolute current density, which lays a foundation for replacing the TIR for two-dimensional imaging of electrochemical reactions in vanadium flow batteries, oxygen/hydrogen evolution reaction, surface treatments, electrochemical corrosion and so on.

We propose a method for sensing the non-specific orientation magnetic field based on a simple frequency domain weak measurement system. The magnetic fields with different directions and magnitudes induce the phase differences. It experimentally and theoretically demonstrates the high sensitivity of the system to phase differences, which confirms the potential of detecting magnetic fields. We obtain a sensitivity of 1.19 nm/mT and a resolution of 0.70 × 10−3 mT. Further, the axial and radial magnetic fields can be calculated simultaneously by using the characteristics of the central wavelength and intensity of the spectrum. The method has a simple set-up and offers high sensitivity, real-time response to the magnetic field, suggesting a new way of enriching the detection of the vector magnetic field.

In this paper, we propose a post-Gaussian filtering theory for weak measurement in the frequency domain, and propose a highly deformed digital filtering technique that can be used to optimize sensors based on weak-frequency measurement techniques. We completed the experimental verification based on the weak measurement total internal reflection sensor. The experimental results show that digital filtering technology can optimize the system in the working range, sensitivity, and resolution of the frequency domain weak measurement system, so that it can reach 0.210 rad, 3210.9 nm/RIU, and 7.12 x 10(-7) RIU, respectively. (C) 2018 Optical Society of America

We propose a self-referential fast detection scheme for a frequency domain weak measurement system for the detection of enantiomeric impurities in chiral molecules. In a transmissive weak measurement system, the optical rotation (OR) is used to modify the pre-selected polarization state and the post-selection polarization state. We obtained the sum and difference of the optical rotations produced by the sample and the standard by rotating the quarter wave plate in the system. Then, we estimate the ratio of chiral molecules to enantiomeric impurities using the ratio of the central wavelength shifts caused by the addition and subtraction states described above. In this paper, our system has an optical resolution of 1.88 &times, 10&minus, 5&deg, At the same time, we completed the detection of the ratio of the two substances in the mixture of L-proline and D-proline in different proportions, which proved that our system can quickly detect the content of enantiomeric impurities in chiral molecules.

The ability to identify L(+)-ascorbic acid from D(-)-isoascorbic acid in medicinal products is of practical interest. Based on the method of frequency domain weak measurement, a set of common optical path sensors for identification of L(+)-ascorbic acid and D(-)-isoascorbic acid is established. By quantificationally analyzing the magnitude and offset direction of the spectral central wavelength, a good identification of the concentration and the optically active forms of ascorbic acid has been achieved. The sensitivity and resolution of the sensor for optical rotation can reach 34.35 nm/° and ${5.53} \times {{10}^{ - 5}}^\circ $5.53×10-5 ∘, respectively. The detection resolution for L(+)-ascorbic acid is ${2.00} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.00×10-4mol/mL, and that for D(-)-isoascorbic acid is ${2.73} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.73×10-4mol/mL. The potential of the sensor in the detection of transparent but optically inactive impurities has been verified by comparative experiments of sodium chloride solution. The sensor also has been applied to identify medicinal vitamin C tablets, which verified the feasibility of the method in optically active pharmaceutical solutions with water-insoluble, optically inactive impurities. Since the sensor has the advantages of high precision, real-time, high robustness, and being non-destructive, it has a great prospect in the field of drug detection containing chiral molecules.