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Polygonum minus (PM) is a tropical medicinal herb that belongs to the family Polygonaceae, widely distributed in Southeast Asia, such as Malaysia, Indonesia, and Thailand. This herb has a sweet and pleasant aroma, commonly used as a flavoring agent. In addition, it is applied as a traditional medicine for multiple diseases, such as fungal infections, poor eyesight, and body aches. Due to its antioxidant and antimicrobial properties, PM is employed as a food additive for delaying or preventing the oxidation reaction of food and as an edible film for protecting food from microbiological contaminants. In livestock, poultry, and aquaculture industries, PM has been proposed as an alternative to traditional growth promoters with anti-parasitic properties. In respect of medicinal applications, PM has been proven to have protective effects on body systems and inhibitory effects on microbes. Moreover, nanotechnology has been applied to improve the efficacy and bioavailability of PM. This review aims to provide insight into the traditional uses, phytochemical properties, and toxicity, as well as applications of PM in food, agricultural, and medicinal fields. [Display omitted] [ABSTRACT FROM AUTHOR]

• We analyze the problem areas and distorted signals that can arise when measuring CSMU using basic white-light interferometry. We specifically focus on addressing the structural areas that are prone to errors, ensuring reliable processing results and improving efficiency. • In the signal processing of the problem areas, we employ characteristic analysis of the distorted signal. By filtering out the disturbed part of the signal and extracting the desired portion containing accurate height information, we are able to reconstruct the 3D topography. • This algorithm can be applied to any traditional optical system utilizing white-light interferometry. It is a simple and accurate approach that only requires a standard experimental setup, making it highly practical. Micro-nanostructures refer to technologies that operate at the nanoscale and provide materials and devices with unique mechanical, physical, and chemical properties. These structures have diverse applications in fields such as microelectronics, biotechnology, aerospace, and metamaterials. As precision machining technology advances, the demand for smaller sizes and higher accuracy of structural units has increased, leading to more compact integration. Consequently, the lossless and high-precision 3D measurement of highly integrated micro-nanostructure components has become increasingly challenging. In this study, we analyzed measurement errors in compactly spaced microstructural units using white-light scanning interferometry and proposed an algorithm to optimize this technology. By combining coherent peak-histogram processing with signal correlation analysis, we were able to improve the measurement accuracy by approximately ten times compared to current mainstream algorithms. To validate our algorithm, we performed experiments using metasurfaces with structural unit spacing at the order of sub-micrometer. The results obtained demonstrated the effectiveness of our algorithm in achieving accurate measurements. [ABSTRACT FROM AUTHOR]

In ptychography, the precise axial distance between the sample and the detector is of vital importance to retrieve the tested object with high quality, but the axial distance error cannot be entirely eliminated in the practical experiments. An autofocusing strategy based on dichotomy is proposed to rapidly correct the axial distance error. In this strategy, the total variation function that is valid for both amplitude- and phase-modulating specimens is applied to determine whether the current distance is smaller or larger than the true distance. Further, the dichotomy is used to exponentially shrink the step-size of the correction by iterative computations, which means that for the early iterations large modified step-size is used and for later iterations only small step-size is considered. Therefore, the dichotomy is beneficial to quickly confirm the accurate axial distance with few computations. Simulations and experiments are conducted to demonstrate that our proposed strategy, based on the extended ptychographic iterative engine (ePIE), is capable of calibrating the sample–detector distance with high accuracy and efficiency. [ABSTRACT FROM AUTHOR]

• In this research, we proposed a novel optical surface shapes measurement method based on conformal mapping-angular phase-shifting interferometry. It paves the way for the application of vortex beams in the field of optical surface shape measurement. It is of great significance to the miniaturization design of high-precision interferometers, and can significantly reduce the experimental cost. • We use a Q-plate in the reference optical path to introduce a 90-degree phase shift, and conformal mapping is used to demodulate the surface shape. • This method not only ensures the accuracy of surface shape measurement; but also avoids the use of expensive precision translation stages; and has specific anti-vibration performance. • The measuring device is simple, compact, easy to operate and low cost. We proposed a novel optical surface shapes measurement method based on conformal mapping-angular phase-shifting interferometry (APSI). This method rotates a Q-plate in the reference light path to introduce a 90-degree phase shift. The mathematical tool of conformal mapping is used for surface shape demodulation. After removing the helical phase in the compound phase, high-precision surface shape measurement results are obtained, and the measurement surface shape deviations are 3.33 nm (PV) and 0.26 nm (RMS). This work paves the way for surface shape measurement and compound phase demodulation using vortex beams. [ABSTRACT FROM AUTHOR]

• This paper proposes a new method to measure the focal lengths of both convex and concave lenses based on the correlation coefficient matching strategy. • This research does not need high-precision displacement equipment or distance measurement devices and expensive optical elements. • The entire measurement system occupies a small space that is easy to set up and operates. This paper proposes a new method to measure the focal lengths of both convex and concave lenses based on the correlation coefficient matching strategy. An interference model related to the real interferogram is built in advance to calculate the correlation coefficients between the simulated interferogram and the real interferogram by traversing parameters method. The parameters related to the maximum correlation coefficients can be used to confirm the focal length. For a biconvex lens with a focal length of 175.578 mm and a biconcave lens with a focal length of −100.001 mm, the relative measurement errors are 0.126% and 0.202%, respectively. Our measurement method is easy and efficient, and the measurement system is compact, easy to set up and low cost, which does not require the expensive precision displacement equipment, the distance measurement systems and the optical components. [ABSTRACT FROM AUTHOR]

• A simple and effective strategy is proposed to measure the focal lengths. • It enables non-contact measurement and no need to measure the distance between optics components. • The entire measurement system occupies a small space that is easy to set up and operates. This paper proposes a new method to measure the focal lengths of both convex and concave lenses based on vortex beam interference. Theoretical analysis illustrates that the maximum intensity distribution of the interferogram is in accordance with the Fermat's spiral, and the spiral coefficient is proportional to the difference between the focal length of the test lens and the distance from the test lens to the camera. In order to calculate the precise focal length, we separately block the light paths to obtain the reference and test beam spots, and get the ratio of these two spot sizes. Then, the ratio and the spiral coefficient are used to determine the focal length. For a biconvex lens with a focal length of 200 mm and a biconcave lens with a focal length of −100 mm, the relative measurement errors are 0.0892 % and 0.0800 %, respectively. This research provides a novel and convenient method for measuring the focal length, and no-sophisticated displacement devices and moving the lens to be measured are required in the measurement. [ABSTRACT FROM AUTHOR]

White-light scanning interferometry is an effective and widely used technology for measuring the microscopic three-dimensional morphology of an object. Its vertical resolution can reach the sub-nanometer level, and its lateral resolution reaches submicron level. However, for the samples containing complex structure or high-density periodic distribution structural units, the measurement results are strongly restricted by magnification and numerical aperture (NA) of the microscopic objective. In this paper, we proposed a three-dimensional reconstruction algorithm for white-light interferograms after super resolution processing, using fast super-resolution convolutional neural networks (FSRCNN) to improve the detailed information of the interferograms, and then we used centroid method combined with the five-step phase-shift method to extract the zero optical path difference (ZOPD) position of the interference signal after super resolution processing. After processed by the proposed method, the interferograms collected by the 10X microscope objective (NA=0.3) recovered the 3D surface is the same as that measured by the 100X microscope objective (NA=0.7), which is proved by the experiment results. [ABSTRACT FROM AUTHOR]

• Only a single interferogram is needed to complete the high-precision measurement of large ROC, which avoids the time-consuming process of acquiring interferograms. • This method uses a large step size to find a rough solution in a wide search range, and then constructs a shrunken range with a small step size based on the rough solution to quickly determine the high-precision measurement results. • Simulation and experimental results show that our method has high measurement accuracy in different interference models but also measurement efficiency is significantly improved. The method, based on searching the maximum or minimum of the metric function in the defined range that can be used to confirm the expected value, has been applied for measuring the large radius of curvature (ROC). The small step size is always needed in the searching range to ensure the measurement accuracy. But in the wide searching range, it will consume much time for finding the expected value. In order to improve the measurement efficiency, this paper proposes a fast measurement strategy for large ROC. This method uses a large step size to find a rough solution in a wide search range, and then constructs a shrunken range with a small step size based on the rough solution to quickly determine the high-precision measurement results. Simulation and experimental results show that the proposed method can be flexibly applied to different interference systems and greatly improve their measurement efficiency. For the tested spherical mirrors with ROC of 41400 mm and 1000 mm, high precision ROC can be obtained in just a few seconds. [ABSTRACT FROM AUTHOR]

• The CCFC method could extract the synthetic-wavelength interferogram from moiré fringe patterns in simultaneous dual-wavelength interferometry without the introduction of other wavelength interferometric information. • Coupled by the multiplication for the conjugate complex functions, only the lower beat-frequency synthetic-wavelength interferometric fringe pattern is derived directly. • The half-band filter in used in CCFC method is appropriate for the different spectral width or carrier spatial frequency. • The necessary introduced linear carrier in CCFC method is merely about 0.0947 times of the carrier in the traditional spatial domain fourier transform demodulation theory numerically. • The introduced carrier is only used to pursue the separation between the ±1 order phase lobes instead of the separation between the different wavelength phase lobes in CCFC method. Simultaneous dual-wavelength interferometry (SDWI) supplies a better solution to extend the measurement range of traditional single-wavelength interferometry with higher efficiency. To decompose the needed longer beat-frequency synthetic-wavelength (λ S) information from the generated moiré fringe pattern in SDWI, a conjugate complex function coupling strategy (CCFC) of interferometric field is proposed in this study. By the Fourier transform and the half-band filter in one side of the spectrum, the positive half spectrum is obtained. The inverse Fourier transform and conjugate operation are performed on the half spectrums to obtain the two conjugate complex functions of the interferometric field. Coupled by the multiplication for the conjugate complex functions, the lower beat-frequency synthetic-wavelength interferometric fringe pattern is derived directly. And if the SDWI is implemented with the π/2 phase shift at λ S , the obtained phase-shift interferogram for λ S could be demodulated by the conventional phase-shift algorithm. Compared with other spatial-domain Fourier transform demodulation theory, the half-band filter used in CCFC method is appropriate for the different spectral width and carrier spatial frequency. The necessary introduced linear carrier is merely about 0.0947 times of the carrier in the former numerically. And it is only used to pursue the separation between the ±1 order phase lobes instead of the separation between the different wavelength phase lobes. The feasibility and applicability of the CCFC method are verified using simulation and experimental results. [ABSTRACT FROM AUTHOR]

• This strategy only uses a single interferogram, which will reduce data acquisition requirements and improve measurement efficiency. • Based on the theoretical analysis of the optical propagation path in the experimental system, a simple method is derived to correct the retrace error and established a matching model. • Simulation and experimental results show that our method not only has high-accuracy of measuring small ROC, but also performs well in the measurement of large ROC. We proposed an iterative correlation coefficient matching strategy for the high-precision measurement of the radius of curvature (ROC), which only needs a single-frame interferogram. This strategy includes two parts: one is to obtain an initial ROC by using the relationship between the ROC and the diameter of the dark ring; other is to further solve a high-precision value by an iterative method. In the iterative part, we simulated a series of interference patterns with each ROC in the setting range, and calculated the correlation coefficient between the each simulated interferogram and the measured interferogram, and searched the maximum of the correlation coefficient that would be used to confirm a new ROC in the next iteration. When the calculated ROCs in the adjacent iterations meet the termination condition, the high-accuracy ROC can be solved. The feasibility of our proposed method has been verified by simulations and experiments. The errors of the test mirrors with the ROC of 101.6 mm and 1000 mm are 0.013% and 0.024% in experiments, respectively. This research provides a simple and feasible method for realizing the high-precision ROC measurement. [ABSTRACT FROM AUTHOR]