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A fast interrogation system of FBG sensors based on low loss jammed-array wideband sawtooth filter
摘要： In this paper, a low loss jammed-array wideband sawtooth (JAWS) filter is built based on a finite reflection virtually imaged array (FRVIA) which has a lower reflectivity of the exit surface compared to a virtually imaged phased array (VIPA). This filter can be used as an edge filter to interrogate the fiber Bragg grating (FBG) sensors. A fast FBG sensing system is set up to detect the strain wave of iron pipe to demonstrate the use of this interrogator. The result shows that the JAWS based interrogation system has advantages of high speed, low loss and high sensitivity.
关键词： JAWS filter,Fiber Bragg grating (FBG) interrogator,Finite reflection virtually imaged array
更新于2025-11-28 14:24:03
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Pixelated-polarization-camera-based polarimetry system for wide real-time optical rotation measurement
摘要： Chirality is an essential consideration in the field of life sciences and pharmaceutical industry because most biomolecules and pharmaceuticals are chiral, and optical rotation measurement is a simple and efficient means for identification, purity test and content detection of chiral materials. However, there are some drawbacks in existing methods, such as small measurement range, non-real-time performance, low measurement accuracy and resolution. This paper presents a novel system to implement optical rotation measurement, and pixelated polarization cameras and Stokes parameters are employed in the system. The polarization information of linearly polarized incident light can be recorded and extracted by a pixelated polarization camera and Stokes parameters respectively. Experiments demonstrate that the proposed system has the necessary advantages for optical rotation measurement, such as real time, wide range ( ?90 ° ～ +90 °), high accuracy ( ±4 ×10?6 °) and high resolution ( 6 ×10?11 °). Thus, this measurement system has great practical prospects in the hospital clinical diagnosis, chemical research, sugar production and pharmaceutical industry.
关键词： pixelated micropolarizer array,optical rotation,chiral drug,polarimetry,Stokes parameters
更新于2025-11-25 10:30:42
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2D Photonic Crystal Nanodisk Array as Electron Transport Layer for Highly Efficient Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) are currently exhibiting reproducible high efficiency; the manufacturing of low cost, scalable electron transport layers (ETLs) is becoming increasingly important. However, this remains a challenge for electron transport layers that exhibit excellent optical/electrical properties while being a thin film of simple morphology. Here we demonstrate the PSC of a 2D photonic crystal nanodisk (ND) array ETL that is compact, but greatly enhances light harvesting. The ND array is fabricated by nanosphere lithography using a monolayer of self-assembled polymer spheres as a physical mask. We fabricate ND arrays of various lattice constants simply by controlling the size of the polymer spheres. Optimal ND arrays exhibit strong forward scattering and optical confinement effects, greatly improving light harvesting in the perovskite layer. We also observe that the ND array improves charge transport by reducing contact resistance with the perovskite layer. ND array ETL PSCs reach 19% maximum power conversion efficiency, with low photocurrent-voltage hysteresis and stable photocurrent output.
关键词： optical confinement,2D photonic crystals,nanodisk array,electron transport layer,perovskite solar cells,forward scattering
更新于2025-11-19 16:46:39
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Upconversion fluorescent nanoparticles based-sensor array for discrimination of the same variety red grape wines
摘要： In this research, a novel fluorescent sensor array based on upconversion nanomaterials (UCNPs) for the discrimination of the same variety red grape wines from different manufacturers was developed. The sensor array was composed of six elements: one positively charged UCNPs modified with guanidine groups (UCNPs@GDN), two negatively charged UCNPs modified with sulfonic acid groups (UCNPs@SO3H) and phosphonic acid groups (UCNPs@PO(OH)2), respectively, and their mixture 1 (UCNPs@GDN + UCNPs@SO3H), mixture 2 (UCNPs@GDN + UCNPs@PO(OH)2) and mixture 3 {UCNPs@GDN + UCNPs@SO3H + UCNPs@PO(OH)2}. The discrimination mechanism is mainly attributed to the emission of those upconversion fluorescent nanoparticles being quenched by organic ingredients that usually exist in red grape wines. The discrimination of red grape wines was carried out by employing UCNPs@GDN, UCNPs@SO3H and UCNPs@PO(OH)2 in pH = 7.0 HEPES buffer, the mixture 1 and mixture 2 in pH = 9.0 PBS buffer, and mixture 3 in pH = 6.0 Tris–HCl buffer. Principal component analysis (PCA) of the data obtained from our established array showed obvious distinction among the nine red grape wines from different manufacturers. The present work is expected to inspire more marvellous research in the fields of UCNPs and red grape wines identification.
关键词： red grape wines,fluorescence quenching,sensor array,upconversion nanoparticles,discrimination
更新于2025-11-14 15:18:02
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Sensor Localization for Highly-Deformed Partially Calibrated Arrays with Moving Targets
摘要： In this letter, a sensor localization technique for highly-deformed partially calibrated arrays with multiple moving targets is proposed. The deformed array is divided into several subarrays. The first subarray is composed of the pre-calibrated sensors, while the sensors in the other subarrays are uncalibrated. The positions of the sensors are estimated from the phase differences between the pre-calibrated sensors and the uncalibrated sensors. The phase ambiguities caused by the highly-deformed sensor positions can be solved using the subspace orthogonality and the movement of multiple targets. Simulation results evaluate the performance of the proposed method, and the Cramer–Rao bounds are compared.
关键词： highly-deformed sensor array,partially calibrated sensor array,phase ambiguity,Sensor localization
更新于2025-09-23 15:23:52
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Research Advances in Phased Array Antennas for Satellite Communications
摘要： Recent research advances in phased array antennas for mobile satellite communications in the State Key Laboratory of Millimeter Waves (SKLMMW) are reviewed, including the Ku-band multiple-panel phased array antenna with almost half sphere coverage, the Ka-band low cost linear phased array module for planar array applications, a single board dual polarized S-band phased array for China S-band mobile satellite communications. The development for fast phased array calibration and measurement is also introduced.
关键词： Mobile Satellite Communications,Phased Array Calibration,Phased Array
更新于2025-09-23 15:23:52
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Polarization-Independent, Narrowband, Near-IR Spectral Filters via Guided Mode Resonances in Ultrathin a-Si Nanopillar Arrays
摘要： We report the optical properties obtained through experiments, simulation, and theory, of ultra-thin (<0.1λ), amorphous Si nanopillar arrays embedded in a thin film of SiO2 designed for narrowband filtering for multi- and hyper-spectral imaging in the near-infrared. The fabricated nanopillar arrays are square-packed with subwavelength periodicity, heights of ~100 nm, and a radius-to-spacing ratio, r/a, of ~0.2. Specular reflection measurements at normal incidence demonstrate that these arrays behave as narrow stopband filters in the near-infrared (λ = 1300-1700 nm) and attain ~90% reflectivity in band and a full width at half maximum as low as 20 nm. Using a combination of full wave simulations and theory, we demonstrate that these narrowband filtering properties arise from efficient grating coupling of light into guided modes of the array because the nanopillar arrays serve as photonic crystal slabs. This phenomenon is known as a guided mode resonance. We discover that the spectral location of these resonances is passively tunable by modifying array geometry and is most sensitive to nanopillar spacing. Theoretical photonic crystal slab band diagrams accurately predict the spectral locations of the observed resonance and provide physical insights into and support the guided mode resonance formulation. This work demonstrates that these ultra-thin all-dielectric nanopillar arrays have advantages over existing hyperspectral filter designs because they are polarization independent and do not suffer from material absorption loss and have significant implications for minimizing imaging device size.
关键词： guided mode resonance,nanopillar array,hyperspectral
更新于2025-09-23 15:23:52
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi, Georgia (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - The Nonuniquness of Solutions to the Synthesis Problems of Plane Array by the Prescribed Amplitude Directivity Pattern
摘要： Studies of a nonlinear synthesis problem for plane equidistant array by the prescribed amplitude directivity pattern (DP) are presented. A characteristic feature of problems of this class is the non-uniqueness and branching of solutions depending on the physical parameters of array. The existence of several types of real solutions is shown. More effective complex solutions branch off from such solutions. The methods of finding the curves of branching the solutions and the numerical algorithms to search the optimal synthesized amplitude DPs are presented.
关键词： amplitude DP,non-uniqueness and branching of solutions,curves of branching,Synthesis problem,plane array
更新于2025-09-23 15:23:52
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Diode Array Near Infrared Spectrometer Calibrations for Composition Analysis of Single Plant Canola (Brassica napus) Seed
摘要： A canola breeder needs an accurate, rapid, non-destructive method for analyzing seeds from a single plant to select the most promising samples for further breeding trials. Near Infrared Spectroscopy (NIRS) is widely used for quantitative analysis of oilseeds in a non-destructive manner. This research was aimed at developing NIRS calibration models for single plant canola seed using a diode array NIRS (950-1650 nm wavelength range), multivariate prediction models, and a mirrored sample cup. Eighteen different NIRS calibration models were developed using 100 samples for each constituent with different pre-processing techniques (mean center, derivatives, variates) and models (PLS, PCR). The relative performance of different calibration models for each constituent was compared using R2, SEP, and ratio performance deviation (RPD) values obtained from the validation set of 30 samples. NIRS models developed using the PLS regression algorithm for moisture content (R2 = 0.97, SEP = 0.32, RPD = 6.13) and oil content (R2 = 0.84, SEP = 0.61, RPD = 4.16) were successful. However, acceptable NIRS models were not obtained for fatty acid and glucosinolates content likely due to limited variability and low levels of the constituent and a narrow wavelength range of the DA-NIR instrument.
关键词： Moisture content,Diode array,Fatty acid composition,Mirrored cup,DA-NIRS,Oil content,Oleic acid,Stearic acid,NIRS calibration model,Palmitic acid
更新于2025-09-23 15:23:52
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Low-loss Loaded Line Phase Shifter for Radar Application in X Band
摘要： Losses in the phase shifters of phased arrays are one of the main limitations of these reconfigurable antennas. This contribution presents the design and measured results of variable phase shifters on triplicate suspended transmission lines in the microwave X-band for variable pointing radar applications. The antenna assembly remains passive and with a very low level of losses in the power distribution network and the phase shifters. PIN or varactor diodes are used to control the load on the transmission line. Each of these components has advantages and disadvantages that are discussed in the communication.
关键词： linear array,phase shifter,Pin diode,varactor,suspended strip
更新于2025-09-23 15:23:52