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Analysis of refraction and scattering image artefacts in x-ray analyzer-based imaging

Chinese physics B 2023年第2期32卷 535-540页

作者：赵立明王天祥马润康顾瑶罗梦丝陈恒王志立葛昕 Department of Optical Engineering School of PhysicsHefei University of TechnologyAnhui 230009China Institute of Biomedical Engineering Shenzhen Bay LaboratoryShenzhen 518067China

X-ray analyzer-based imaging(ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorption, refraction, and scattering properties of the investigated sample. However, x-ray ABI setups can be susceptible to external vibrations, and mechanical imprecisions of system components, e.g., the precision of motor, which are unavoidable in practical experiments. Those factors will provoke deviations of analyzer angular positions and hence errors in the acquired image ***, those errors will introduce artefacts in the retrieved refraction and scattering images. These artefacts are disadvantageous for further image interpretation and tomographic reconstruction. For this purpose, this work aims to analyze image artefacts resulting from deviations of analyzer angular positions. Analytical expressions of the refraction and scattering image artefacts are derived theoretically and validated by synchrotron radiation experiments. The results show that for the refraction image, the artefact is independent of the sample’s absorption and scattering signals. By contrast, artefact of the scattering image is dependent on both the sample’s refraction and scattering signals, but not on absorption ***, the effect of deviations of analyzer angular positions on the accuracy of the retrieved images is investigated,which can be of use for optimization of data acquisition. This work offers the possibility to develop advanced multi-contrast image retrieval algorithms that suppress artefacts in the retrieved refraction and scattering images in x-ray analyzer-based imaging.

关键词： x-ray imaging analyzer-based imaging image artefacts

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Investigations of moiréartifacts induced by flux fluctuations in x-ray dark-field imaging

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Chinese physics B 2023年第3期32卷 621-628页

作者：王志立陈子涵顾瑶陈恒葛昕 Department of Optical Engineering School of PhysicsHefei University of TechnologyHefei 230009China Institute of Biomedical Engineering Shenzhen Bay LaboratoryShenzhen 518067China

X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years.X-ray dark-field image is commonly retrieved by using discrete Fourier transform from the acquired phasestepping *** retrieval process assumes a constant phase step size and a constant flux for each stepped grating ***,stepping errors and flux fluctuations inevitably occur due to external vibrations and/or thermal drift during data *** studies have shown that those influences introduce errors in the acquired phase-stepping data,which cause obvious moiréartifacts in the retrieved refraction *** work investigates moiréartifacts in x-ray dark-field imaging as a result of flux *** the retrieved mean intensity,amplitude,visibility and dark-field images,the dependence of moiréartifacts on flux fluctuation factors is theoretically derived respectively by using a first-order Taylor series *** of synchrotron radiation experiments verify the validity of the derived analytical *** spatial frequency characteristics of moiréartifacts are analyzed and compared to those induced by phase-stepping *** illustrates that moiréartifacts can be estimated by a weighted mean of flux fluctuation factors,with the weighting factors dependent on the moiréphase and different greatly for each retrieved ***,moiréartifacts can even be affected by object’s features not displayed in the particular *** results can be used to interpret images correctly,identify sources of moiréartifacts,and develop dedicated algorithms to remove moiréartifacts in the retrieved multi-contrast images.

关键词： x-ray imaging dark-field imaging moiréartifacts flux fluctuations

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Synthesis of novel high-entropy diborides with high-efficiency electromagnetic wave absorption and excellent thermal stability

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Journal of Advanced Ceramics 2025年第2期14卷 185-197页

作者： Chencheng Liu Qingyun Chen Peng Sun Xingye Wang Shuyi Zeng Qijie Chen Tong Zhu Yi Zhu Wenlong Zhang Hui Song Yuezhong Wang Kazuhito Nishimura Huasong Liu Nan Jiang College of Physics and Electronic Information Engineering Guilin University of TechnologyGuilin 541004China State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Tianjin Key Laboratory of Optical Thin Films Tianjin Jinhang Technical Physics InstituteTianjin 300308China

Ceramic materials have obvious advantages in thermal stability,but impedance mismatch limits their ability to attenuate electromagnetic(EM)***,a novel series of high-entropy(V_(0.2)Nb_(0.2)Zr_(0.2)Ta_(0.2)X_(0.2))B_(2)(X=Mo,Ti,and Hf)ceramics were successfully synthesized via ultrafast high-temperature sintering(UHS)apparatus based on joule *** results indicated that the effect of high-entropy component on the magnetic loss of the system was relatively small,but the effect on the dielectric loss was *** them,the(V_(0.2)Nb_(0.2)Zr_(0.2)Ta_(0.2)Ti_(0.2))B_(2)(HEB-Ti)sample demonstrated superior absorbing properties due to relatively moderate dielectric loss and optimal EM impedance ***,because of its relatively moderate attenuation constant,it could achieve the maximum penetration of the EM wave and the minimum reflection after absorbing *** a result,the minimum reflection loss(RL_(min))was as low as−40.7 dB,and the effective absorption band covered the entire low-frequency range from 2 to 8 *** excellent absorption performance was mainly due to the synergistic effect of various dielectric attenuation mechanisms,including defect polarization,dipole polarization,and conduction ***,thermogravimetric(TG)analysis showed that the sample exhibited excellent thermal stability and could withstand temperatures up to 550℃in air and 1000℃in an argon gas *** relevant work could provide meaningful references for the design of new high-performance ceramic wave-absorbing materials.

关键词： high-entropy diborides(HEBs) ultrafast high-temperature sintering(UHS) electromagnetic(EM)wave absorption impedance matching

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All-fiber delivery of 100 W single-frequency laser through 100 m anti-resonant hollow-core fiber without stimulated Brillouin scattering

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High Power Laser Science and engineering 2024年第6期12卷 277-282页

作者： Shoufei Gao Wenxiang Zha Yujun Feng Zhixi Liang Yizhi Sun Xiaobo Yang Yingying Wang Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communication Institute of Photonics TechnologyJinan UniversityGuangzhouChina College of Physics and Optoelectronic Engineering Jinan UniversityGuangzhouChina Institute of Applied Electronics China Academy of Engineering PhysicsMianyangChina Linfiber Technology(Nantong)Co. Ltd.NantongChina

The flexible delivery of single-frequency lasers is far more challenging than that of conventional lasers due to the onset of stimulated Brillouin scattering (SBS).Here we present the successful delivery of 100 W single-frequency laser power through 100 m of anti-resonant hollow-core fiber (AR-HCF) in an all-fiber configuration,with the absence of *** employing a custom-designed AR-HCF with a mode-field diameter matching that of a large-mode-area panda fiber the system achieves high coupling efficiency without the need for free-space components or fiber *** AR-HCF attains a transmission efficiency of 92%,delivering an output power of 100.3 W with a beam quality factor(M^(2)) of *** absence of SBS is confirmed through monitoring backward light,which shows no increase in intensity This all-fiber architecture ensures high stability,compactness and efficiency,potentially expanding the application scope of single-frequency lasers in high-precision metrology,optical communication,light detection and ranging systems gravitational wave detection and other advanced applications.

关键词： all-fiber delivery hollow-core fiber power single-frequency laser

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In situ fiber-optic detection of photocorrosion in electrochemically grown CuO photocathodes

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Photonics Research 2025年第3期13卷 561-571页

作者： TIANSHENG HUANG TONGYU WU QI FANG GUANGZHENG LUO LI-PENG SUN BAI-OU GUAN Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China College of Physics&Optoelectronic Engineering Jinan UniversityGuangzhou 510632China

Semiconductor metal oxides with narrow bandgap have emerged as a promising platform for photoelectrochemical reactions,yet their photoelectron-induced photocorrosion effect has been a limitation for their wider *** the conversion processes concomitant with photoelectrochemical reaction at the electrode-electrolyte interface plays a crucial role in revealing the corrosion mechanisms and advancing the development of efficient ***,accurately and in situ tracking these dynamic chemical events remains a great challenge due to the fact that reaction processes occur at nanoscale ***,we track the electrochemical growth and conversion of copper nanostructures at interface by the evanescent field of the surface plasmon wave by using a gold-coated optical fiber as an electrochemical electrode and light sensing *** results exhibit correlation between redox processes of copper species and plasmonic ***,in situ fiber-optic detection reveals the photocorrosion dynamics under photoelectrochemical reaction,including photoelectron-induced self-reduction of copper oxide and self-oxidation of cuprous *** demonstrations facilitate not only the diagnosis for the health condition of photocathode nanomaterial,but also the understanding of the underlying reaction mechanism,and thus are potentially crucial for advancing the development of highly efficient photocathodes in future energy applications.

关键词： fiber optic sensing photoelectrochemical reaction revealing corrosion mechanisms photoelectrochemical reactionsyet situ detection conversion processes photocorrosion semiconductor metal oxides

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Research on high-repetition-frequency and high-power nanosecond laser cleaning technology 4

Research on high-repetition-frequency and high-power nanosec...

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4th Optics Frontier Conference, OFS 2024

作者： Dong, Xue-Yan Zhang, Cheng-Gong Kou, Yang Liu, Zi-Lei Yan, Xing-Wei Yang, Pei-Jiang Li, Xinlei Zhang, Tian-Yu Yang, Feng-Tu Institute of Optical Physics and Engineering Technology Qilu Zhongke Shandong Jinan250000 China

ISBN: (纸本)9781510682269

With the advantages of safety, non-contact operation, high precision and real-time feedback, laser cleaning technology plays an important role in the field of intelligent manufacturing. In this study, a nanosecond pulsed laser with a wavelength of 1064 nm, a repetition frequency of 20 kHz, a pulse width of 70 ns, an average power of 3000 W, and a spot size of 40 mm*0.5 mm was used as the laser cleaning light source. Additionally, a laser cleaning prototype was constructed with a three-dimensional gantry displacement platform. With a scanning speed of 160 mm/s, a spot interval of 25 mm, and a laser energy density of 750 mJ/cm2, the oxide film on the surface of marine steel was completely removed, achieving a good cleaning effect and a cleaning efficiency of up to 20 m2/h. The entire cleaning process was achieved without dust emission. Our high-repetition-frequency, high-power nanosecond laser cleaning prototype is highly effective in removing rust from marine corrosion class B steel. © 2024 SPIE.

关键词： Seawater corrosion

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Research on Fiber Coupling Efficiency of 178 mJ Nanosecond Pulsed Lasers 19

Research on Fiber Coupling Efficiency of 178 mJ Nanosecond P...

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19th National Conference on Laser technology and Optoelectronics

作者： Dong, Xue-Yan Zhang, Cheng-Gong Li, Xin-Lei Liu, Kai Kou, Yang Yan, Xing-Wei Yang, Pei-Jiang Liu, Zi-Lei Institute of Optical Physics and Engineering Technology Qilu Zhongke Shandong Jinan250000 China

ISBN: (纸本)9781510683228

Nanosecond pulsed lasers with high single-pulse energy show significant advantages in industrial fields such as material processing and laser cleaning. However, the traditional free-space or waveguide transmission methods are often limited by high energy loss, transmission distance, and difficulty in realizing flexible transmission in practical applications. This research is dedicated to exploring the realization of efficient, stable and flexible transmission of nanosecond pulsed lasers with high single-pulse energy. By combining the simulation of the effect of the decenter and tilt of the optical fiber on the coupling efficiency with the ZEMAX software, we have solved the problem of the spot defocusing in the horizontal and vertical directions caused by the thermal effect of the slab laser by precisely adjusting and optimizing the spatial positions of the lenses in the focusing system and the beam shaping system. This reduces the energy loss of the laser during the optical fiber transmission process and improves the transmission efficiency and stability. Finally, a 178 mJ laser is coupled into an optical fiber with a core diameter of 800 μm. The coupling efficiency is as high as 96% with a flexible transmission distance of 15 m. Our research provides strong support for the development and application of laser technology. © 2024 SPIE.

关键词： optical fiber coupling

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Density waves of vortex fluids on a sphere

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Communications in Theoretical physics 2025年第4期77卷 159-166页

作者： Yanqi Xiong Zhijun Zou Liang Luo Key Laboratory of Hunan Province on Information Photonics and Freespace Optical Communications School of Physics and Electronic ScienceHunan Institute of Science and TechnologyYueyang 414006China Graduate School of China Academy of Engineering Physics Beijing 100193China

We aim to find one highly nontrivial example of the solutions to the vortex fluid dynamical equation on the unit sphere(S^(2))and compare it with the numerical *** the rigid rotating steady solution for vortex fluids on S^(2)is already known to us,we consider the perturbations above *** decomposing the perturbation of the vortex number density and vortex charge density into spherical harmonics,we find that the perturbations are propagating *** be precise,the velocities for different single-mode vortex number density waves are all the same,while the velocities for single-mode vortex charge density waves depend on the degree of the spherical harmonics l,which is a signal of the existence of ***,we find that there is a beat phenomenon for the positive(or negative)vortex density *** simulation based on the canonical equations for the point vortex model agrees perfectly with our theoretical calculations.

关键词： quantum vortex 2D sphere superfluid density wave dispersion ome

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Highly-reflective facet-coated multi-wavelength DFB laser array with exact wavelength spacings

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Optics Express 2024年第2期32卷 1843-1850页

作者： Wang, Ling Lv, Gen Fan, Yaqiang Tang, Kaifei Sun, Zhenxing Gong, Yangyang Chen, Xiangfei Chiu, Yi-Jen Xiao, Rulei Zhou, Yating Key Laboratory of Intelligent Optical Sensing and Manipulation the Ministry of Education National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciences Institute of Optical Communication Engineering Nanjing University Nanjing210093 China School of Mathematics & Physics and Chemical Engineering Changzhou Institute of Technology Jiangsu Changzhou213032 China Institute of Electro-Optical Engineering and Semiconductor Technology Research Development Center National Sun Yat-Sen University Kaohsiung80424 Taiwan

A distributed feedback (DFB) laser array of twenty wavelengths with highly reflective and anti-reflective (HR-AR) coated facets is both theoretically analyzed and experimentally validated. While the HR facet coating enhances high wall-plug efficiency, it inadvertently introduces a random facet grating phase, thereby compromising the lasing wavelength’s predictability and the stability of the single-longitudinal-mode (SLM). In this study, two key advancements are introduced: first, the precisely spaced wavelength is achieved with an error of within ±0.2 nm using the reconstruction-equivalent-chirp (REC) technique;second, the random grating phase on the HR-coated facet is compensated by a controllable distributed phase shift through a two-section laser structure. The SLM stability can be improved while the wavelength can be continuously tuned to the standard wavelength grid. The overall chip size is compact with an area of 4000 × 500 µm2. The proposed laser array has a light power intensity above 13 dBm per wavelength, a high side mode suppression ratio above 50 dB, and low relative intensity noise under -160 dB/Hz. These attributes make it apt for deployment in DWDM-based optical communication systems and as a light source for optical I/O. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Distributed feedback lasers

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Buried interface bridging for inverted cesium-formamidinium triiodide perovskite solar cells with long operational stability

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Science China Chemistry 2025年第1期68卷 163-173页

作者： Chenhui Zhang Chunjun Liang Fulin Sun Ting Zhu Xinghai Huang Yuzhu Guo Xinyu Guo Kunyang Ge Dan Li Fangtian You Zhiqun He Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optoelectronic TechnologyBeijing Jiaotong UniversityBeijing 100044China Department of Physics School of Physical Science and EngineeringBeijing Jiaotong UniversityBeijing 100044China

In the field of perovskite solar cells(PSCs),the research on defects in the buried interface has been relatively limited due to its non-exposure;however,this interface significantly impacts the performance enhancement of inverted *** study employs phenylethylammonium chloride(PEACl)molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs)and facilitate the uniform nucleation and growth of perovskite films on the ***,the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination *** these optimizations,the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE)of 24.11%,with significant improvements in storage,thermal stability,and operational *** noteworthy is the device's performance in an unencapsulated state,whereas after 1,500 hours of continuous light operation stability testing,it retains 97%of its original *** study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.

关键词： defect-induced recombination buried interfaces inverted perovskite solar cells crystallization lattice mismatch

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