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Fixed-time synchronization of fractional-order complex-valued delayed neural networks with discontinuous activation functions

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Neural Computing and Applications 2024年第26期36卷 15947-15959页

作者： Ding, Zhixia Wang, Jianhao Li, Sai Yang, Le Wang, Liheng School of Electrical and Information Engineering Wuhan Institute of Technology Wuhan430205 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan430205 China

This article concentrates on the fixed-time synchronization (FXTS) of fractional-order complex-valued delayed neural networks with discontinuous activation functions. On the basis of the nonsmooth analysis, differential inclusion theory, Lyapunov stability theorem and complex function theory, some sufficient conditions are developed to guarantee the FXTS of such system by designing a novel fractional-order complex-valued controller. The fixed-time synchronization can make up the limitation of the previous finite-time synchronization results, that is, fixed-time synchronization time relies on the parameters of controller, which is independent of initial values. Additionally, the upper limit of synchronization time is estimated accurately. Furthermore, our results improve some finite-time synchronization and fixed-time synchronization ones. Finally, the effectiveness of theoretical results is demonstrated by some numerical simulations. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.

关键词： Chemical activation

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Hong-Ou-Mandel interference with absorption and dispersion from rare earth ions 2

Hong-Ou-Mandel interference with absorption and dispersion f...

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2nd International Conference on optical Communication and optical information Processing, OCOIP 2024

作者： Li, Wei Wang, Hong-Wei Ding, Chunling Hao, Xiangying Yuan, Chenzhi Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

ISBN: (数字)9781510688995

ISBN: (纸本)9781510688988

The coherent interactions between photons and rare earth ion ensembles are crucial for quantum storage and quantum information processing. Hong-Ou-Mandel (HOM) interference, a well-known quantum interference phenomenon, has been widely used in precision measurement applications. However, there have been no reports to date on observing coherent interactions between light and ionic ensembles using HOM interferometry. In this study, we experimentally generated entangled photons from two 10-mm-long type-0 phase-matched PPKTP crystals. Then we constructed a HOM interferometer and achieved a HOM dip with a visibility of 82.4% and a width of 152.5 ± 0.2 fs. Finally, we inserted a Nd3+ : YVO4 (rare earth ion) crystal into the optical path and successfully observed the splitting of the HOM dip. This experiment may provide valuable insights into light-matter interactions and could be beneficial for quantum storage applications. © 2025 SPIE.

关键词： Photons

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Optimal exposure selection of high dynamic range-based reflection compensation for printed circuit board reconstruction using structured light 3D measurement system 12

Optimal exposure selection of high dynamic range-based refle...

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SPIE 12th International Symposium on Multispectral Image Processing and pattern recognition, MIPPR 2023

作者： Wang, He Zhu, Ying Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan China

ISBN: (数字)9781510674967

ISBN: (纸本)9781510674950

Structured light (SL) scanning in industrial metrology offers the advantages of non-contact measurement, high-speed operation, and high precision. However, fringes may exhibit excessive modulation when measuring highly reflective metal parts, leading to the calculation of invalid phases and the reconstruction of abnormal point clouds. High dynamic range (HDR) scanning is a commonly used approach to address this issue, but the optimal exposure time using this method is usually influenced by the reflective properties of the object. In this paper, we propose an optimal exposure time selection method based on the clustering of images in the fringe modulation. Firstly, we acquire modulation degree images containing only objects. Subsequently, the K-Means method is employed to cluster the modulation degree images. The K best exposure times are calculated based on the average maximum gray value of the fringe images in each cluster. Finally, K sets of fused fringe images are captured and utilized to reconstruct three-dimensional (3D) information with enhanced coverage. Using our method, the three-dimensional information of the printed circuit board (PCB) is reconstructed, achieving an improved coverage rate of 98.1% compared to the 88.3% coverage rate obtained from a single-shot capture. Additionally, our method achieves a measurement accuracy of 0.08mm. Experimental results demonstrate that the proposed method efficiently selects the optimal fusion exposure time, making it suitable for measuring highly reflective PCBs. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Image enhancement

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Compact optical fiber laser frequency comb based on acetylene-filled photonic microcell

Compact optical fiber laser frequency comb based on acetylen...

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2024 Conference on Spectral Technology and Applications, CSTA 2024

作者： Li, Kangqiao Chen, Qingqing Gao, Yanwei Wu, Shun Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

ISBN: (纸本)9781510683082

We demonstrated a compact optical fiber frequency comb stabilized to an acetylene-filled photonic microcell. The erbium fiber oscillator with 109 MHz repetition frequency achieved self-start, and days of stable mode-locking based on a figure-9 configuration. The laser was assembled into a 270 × 280 × 45 mm3 box with precise temperature-control around 25 ℃. The CW reference was stabilized to an acetylene-filled hollow-core photonic crystal fiber (HC-PCF) in a sealed box with dimensions of 385 ×260 ×86 mm3. The 19-cell HC-PCF has a core diameter of 30 μm and length of 3.9m filled with 100 ~ 200 mTorr (13.3 ~ 26.7 Pa) acetylene gas. A sub-Doppler absorption feature of P(13) line from the v1+v3 overtone transition was obtained based on saturated absorption spectroscopy. The optimized sub-Doppler feature had a narrow linewidth of 16 MHz and a signal-to-noise ratio (SNR) of ~ 40. The short-term fractional instability of fr was 3.47 ×10-12 at 1 s gate time, and 1.81 ×10-13 at 100 s gate time, with a standard deviation of 0.3 mHz. The RF beatnote (fb) exhibited a fractional instability of 1.53 ×10-11 at 1 s gate time for a four-hour measurement in laboratory environment. The overall size of the comb system is expected to be 443 × 270 × 131 mm3 including all the locking electronics. Our approach of acetylene-stabilized fiber comb offers a feasible solution to help fiber combs move from laboratory to outdoors applications such as fiber sensing, laser stabilization and spectrum analysis. © 2024 SPIE.

关键词： Fiber lasers

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Curvature and temperature sensing based on liquid-core fiber Bragg grating 7

Curvature and temperature sensing based on liquid-core fiber...

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7th Global Intelligent Industry Conference, GIIC 2024

作者： Ke, Zhi-Hong Liu, Shu-Hui Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

ISBN: (纸本)9781510682986

A liquid core fiber Bragg grating (FBG) sensor is proposed for curvature and temperature sensing. The sensor is fabricated by inscribing two FBGs with different periods on both sides of the hollow-core fiber(HCF) using femtosecond laser direct writing technique, and filling the hollow core with liquid. Due to the overlap of propagation modes formed by liquid fibre cores and the grating, the reflection spectrum of FBG exhibits two well-defined resonance peaks. Bending influences the fibre gratings on both sides of the air core differently, causing the intensity of the reflection peaks of the gratings to change. In the small curvature range, Bragg grating close to and far from the direction of bending are stretched and compressed respectively, thus the resonance peaks show opposite trends, which can be used to determine the direction of bending. As the curvature further increases, bending loss is the dominating factor that affects the reflectivity, and the peak intensity exhibit a decrease response, with sensitivity of -2.15468 dB/m-1and -1.93504 dB/m-1. The temperature sensitivity of the FBG is improved due to the presence of the liquid with high thermo-optic coefficient, and blue shift response is observed when temperature is increased, with sensitivities of 86.67 pm/℃ and 66.61 pm/℃, respectively. © 2024 SPIE.

关键词： Femtosecond lasers

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Liquid-core long period grating temperature sensor based on femtosecond writing 7

Liquid-core long period grating temperature sensor based on ...

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7th Global Intelligent Industry Conference, GIIC 2024

作者： Zhao, Shengguo Liu, Shuhui Zhao, Kaixin Tao, Tianlong Ke, Zhihong Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

ISBN: (纸本)9781510682986

Long-period fiber grating (LPFG) based temperature sensors have a wide range of applications in biological and chemical sensing. However, conventional LPFGs exhibit low sensitivity because of the low thermo-optic coefficient of silica. In this paper, a novel liquid-core LPFG device is proposed. The sensor is fabricated by using femtosecond laser to periodically inscribe long-period grating onto the silica material near the air core of the hollow-core fiber (HCF). Liquid with a high refractive index (RI) is filled into the HCF to form a liquid-core waveguide, and transmission peaks resulting from the grating resonance are observed because of the coupling between the fundamental mode and cladding modes. Experimental results show that the temperature sensitivity of the LPFG is highly dependent on the RI of the filled liquid. When liquid with a refractive index of 1.476 is filled in the fiber core, the temperature sensitivity is approximately 6.34 nm/°C in the range of 27-40°C. The device has great potential for applications in areas such as medicine, and chemical industry. © 2024 SPIE.

关键词： Femtosecond lasers

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Finite-time Mittag-Leffler synchronization of fractional-order complex-valued memristive neural networks with time delay

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Chinese Physics B 2022年第10期31卷 297-306页

作者： Guan Wang Zhixia Ding Sai Li Le Yang Rui Jiao Hubei Key Laboratory of Optical Information and Pattern Recognition School of Electrical and Information EngineeringWuhan Institute of TechnologyWuhan 430205China

Without dividing the complex-valued systems into two real-valued ones, a class of fractional-order complex-valued memristive neural networks(FCVMNNs) with time delay is investigated. Firstly, based on the complex-valued sign function, a novel complex-valued feedback controller is devised to research such systems. Under the framework of Filippov solution, differential inclusion theory and Lyapunov stability theorem, the finite-time Mittag-Leffler synchronization(FTMLS) of FCVMNNs with time delay can be realized. Meanwhile, the upper bound of the synchronization settling time(SST) is less conservative than previous results. In addition, by adjusting controller parameters, the global asymptotic synchronization of FCVMNNs with time delay can also be realized, which improves and enrich some existing results. Lastly,some simulation examples are designed to verify the validity of conclusions.

关键词： finite-time Mittag-Leffler synchronization fractional-order complex-valued memristive neural networks time delay

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Alcohol-dispersed polymer complex as an effective and durable interface modifier for n-i-p perovskite solar cells

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Journal of Energy Chemistry 2024年第6期93卷 243-252,I0007页

作者： Chang Shi Jiangling Li Shuping Xiao Ziyi Wang Wuchen Xiang Rui Wu Yang Liu Yinhua Zhou Weijun Ke Guojia Fang Pingli Qin Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan 430205HubeiChina Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074HubeiChina School of Physics and Technology Key Laboratory of Artificial Micro-and Nano-structures of the Ministry of Education and School of Physics and TechnologyWuhan UniversityWuhan 430072HubeiChina

Abundant interfacial defects remain a significant challenge that hampers both the efficiency and stability of perovskite solar cells(PSCs).Herein,an alcohol-dispersed conducting polymer complex,denoted as PEDOT:F(Poly(3,4-ethylene dioxythiophene):Perfluorinated sulfonic acid ionomers),is introduced into the interface between perovskite and hole transporting layer in regular-structured ***:F serves as a multi-functional interface layer(filling grain boundaries and covering perovskite's grain-surface)to achieve a robust interaction with organic groups within perovskites,which could induce a structural transformation of PEDOT to increase its conductivity for the efficient ***,the strong interaction between PEDOT and perovskites could promote an effective coupling of undercoordinated Pb~(2+)ions with the lone electron pairs near O&S atoms in PEDOT molecules,thereby enhancing defect ***,PEDOT:F with inherent hydrophobic properties prevents effectively moisture invasion into perovskites for the improved long-term stability of the ***,the PEDOT:F-based PSCs achieved a champion efficiency of 24.81%,and maintained ca.92%of their initial efficiency after 7680 h of storage in a dry air environment,accompanied by the enhanced photothermal stability.

关键词： Alcohol-dispersed conducting polymer complex Interface passivation Grain boundaries Device stability Perovskite solar cells

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Toward a compact fiber comb with 1.66×10^(-12)instability based on acetylene-filled photonic microcells

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Chinese Optics Letters 2024年第8期22卷 29-34页

作者： Qingqing Chen Yongqi Li Shun Wu Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan 430205China

We demonstrated an optical fiber frequency comb stabilized to an acetylene-filled photonic *** short-term instability of the comb at 1 s gate time was 1.66×10^(-12)for a 4.2-h measurement in a laboratory environment with air *** is the best short-term stability reported for a compact fiber comb stabilized to an acetylene-filled photonic microcell at telecom *** is particularly significant in the development of compact fiber combs with target instability of 10^(-13).Such a device has the potential to serve as an alternative to GPS in areas lacking signal coverage,including remote locations,regions with adverse weather conditions,and military intelligence areas.

关键词： optical frequency comb gas-filled photonic microcell hollow-core photonic crystal fiber

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Study of the 6.x nm short wavelength radiation spectra of laser-produced erbium plasmas for BEUV lithography

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Plasma Science and Technology 2023年第6期25卷 41-51页

作者：吴涛王倩陈柳安陆培祥 Hubei Key Laboratory of Optical Information and Pattern Recognition School of Optical Information and Energy EngineeringWuhan Institute of TechnologyWuhan 430205People's Republic of China Guangdong Intelligent Robotics Institute Dongguan 523808People's Republic of China

Beyond extreme ultraviolet(BEUV)radiation with a wavelength of 6.x nm for lithography is responsible for reducing the source wavelength to enable continued miniaturization of semiconductor *** this work,the Required BEUV light at 6.x nm wavelength was generated in dense and hot Nd:YAG laser-produced Er *** spectral contributions from the 4p–4d and 4d–4f transitions of singly,doubly and triply excited states of Er XXIV–Er XXXII in the BEUV band were calculated using Cowan and the Flexible Atomic *** was also found that the radiative transitions between multiply excited states dominate the narrow wavelength window around 6.x *** the assumption of collisional radiative equilibrium of the laser-produced Er plasmas,the relative ion abundance in the experiment was *** the Boltzmann quantum state energy level distribution and Gram–Charlier fitting function of unresolved transition arrays(UTAs),the synthetic spectrum around 6.x nm was finally obtained and compared with the experimental *** spatio-temporal distributions of electron density and electron temperature were calculated based on radiation hydrodynamic simulation in order to identify the contributions of various ionic states to the UTAs arising from the Er plasmas near 6.x nm.

关键词： laser-produced plasmas unresolved transition array collisional radiative equilibrium

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