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A Semi-supervised Low-Light Image Enhancement with Color Guidance

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A Semi-supervised Low-Light Image Enhancement with Color Gui...

Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA)

作者： Yuxin Wang Shuolin Yang Qianxi Wu Zhishuo Zhang Yunxia Liu Yang Yang Yakui Dong Cheng Fei Junliang Liu Lili Wang Shuzhen Fan Yongfu Li Center for Optics Research and Engineering (CORE) Shandong University Qingdao China Key Laboratory of Laser & Infrared System Ministry of Education Shandong University Qingdao China School of Information Science and Technology Shandong University Qingdao China

ISBN: (数字)9798350367331

ISBN: (纸本)9798350367348

Low-light image enhancement (LLIE) has found extensive applications in surveillance and related fields. Current deep learning-based algorithms have demonstrated significant advantages over traditional methods for LLIE. However, the issue of color distortion still remains a challenge. This paper proposes a semi-supervised curve estimation and restoration network that consists of two cascaded sub-networks with distinct functionalities. The first-level sub-network applies specific constraints to enhance different regions based on their brightness levels. The second-level sub-network is trained using superpixel color consistency loss and global histogram loss to effectively correct color distortion. Experimental results demonstrate that the proposed method achieves satisfactory outcomes in both visual quality and evaluation metrics.

关键词： Measurement Histograms Visualization Image color analysis Surveillance Brightness Estimation Distortion Image restoration Image enhancement

Generation of high-repetition-rate, high-power, few-cycle, 2-µm laser pulses with a single-stage all-fiber nonlinear compressor

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Optics Letters 2025年第12期50卷 3852-3855页

作者： Zhen Yuan Kejian Yang Yang Li Jingjie Hao Heyan Liu Zhongben Pan Jinwei Zhang Yizhou Liu Tianli Feng Key Laboratory of Laser & Infrared System Ministry of Education School of Information Science and Engineering Shandong University Qingdao 266237 China Institute of Novel Semiconductors State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China yizhou.liu@***

We demonstrate a high-repetition-rate, high-power, few-cycle 2-µm laser employing a single-stage, all-fiber nonlinear pulse compressor. The compressor consists of three cascaded dispersion-compensating fibers that are spliced, with group velocity dispersions of −0.095 ps 2 /m, 0.137 ps 2 /m, and −0.076 ps 2 /m, respectively. The splicing losses caused by the different mode-field diameters were carefully minimized to 0.8 dB and 0.23 dB. A home-built 51.6-MHz, 8.26-W, 578-fs Tm-doped laser was used as the driving laser. This nonlinear fiber compressor realized a compression ratio of 17, reducing the pulse duration to 34 fs, based on the Gaussian assumption. The interaction between the accumulated nonlinear phase and dispersion was analyzed to optimize the characteristics of the compressed pulse. Consequently, laser pulses with 4.4-W average power and a 34-fs duration were generated.

关键词： laser sources Nonlinear optical fibers Nonlinear parametric processes Raman scattering Thulium doped fiber lasers Thulium-doped fiber amplifiers

Single-Frequency Continuous-Wave Solid-State 363.8-Nm Ultraviolet Source Generation by Frequency Tripling of a 1091-Nm Fiber laser

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SSRN 2025年

作者： Wei, Zhenshuai Li, Fengtian Men, Shaojie Haung, Lu Zhao, Zhigang Cong, Zhenhua Liu, Zhaojun School of Information Science and Engineering Shandong University Qingdao266237 China Key Laboratory of Laser & Infrared System Shandong University Ministry of Education Qingdao266237 China Signal & Communication Research Institute China Academy of Railway Sciences Corporation Limited Beijing10081 China Shandong Provincial Key Laboratory of Laser Technology and Application Qingdao266237 China

A single-frequency continuous-wave (CW) ultraviolet (UV) solid-state source at 363.8 nm has been demonstrated through the frequency tripling of a high-power, single-frequency, linearly-polarized (LP) 1091-nm laser. This 1091-nm laser, which features a homemade single-frequency distributed Bragg reflector (DBR) seed and can deliver 78-W average power with an optical signal-to-noise ratio (OSNR) exceeding 63 dB and a polarization extinction ratio (PER) of ~15.8 dB. Employing two cascaded periodically poled Mg-doped lithium niobate (PPMgLN) crystals, whose lengths are 30 mm and 20 mm, a single-frequency 545.5-nm source with an average power of 1.85 W and a single-frequency 363.8-nm source with an average power of higher than 20 mW were obtained, when the input power of the 1091-nm laser was just 11.78 W. To the best of our knowledge, this is the first single-frequency solid-state UV source at 363.8 nm, which is usually provided by argon-ion gas laser, thus offering a potential alternative for semiconductor chip inspection applications. © 2025, The Authors. All rights reserved.

关键词： Fiber lasers

Hybrid CsPbBr3@CP-1 composites with enhanced stability and dual-emitting for white LED and photoelectrical applications

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Progress in Natural Science: Materials International 2025年

作者： Zhou, Hao Fan, Qingxin Zhu, Shaowen Zhou, Minjie Liu, Jingyi Li, Zhiqiang Jin, Bing Zhang, Xiandong Liu, Min Wang, Yilin School of Integrated Circuits Shandong Technology Center of Nanodevices and Integration Shandong University Jinan250100 China Institute of Molecular Sciences and Engineering Institute of Frontier and Interdisciplinary Science Shandong University Qingdao266235 China Key Laboratory of Laser and Infrared System Ministry of Education Center for Optics and Research Engineer Shandong University Qingdao266235 China Shandong Wanbo Technologies Co. LTD Jinan250100 China

The halide perovskite CsPbBr3 quantum dots (QDs) exhibit remarkable potential for diverse applications, attributed to their distinctive optical properties. However, their poor stability hinders practical implementation. In this study, we enhanced the stability of perovskite QDs by incorporating CsPbBr3 QDs into a coordination polymer called CP-1. CP-1 features excellent photoluminescent properties thanks to its ligand trans,trans-9,10-bis(4-pyridylethenyl) anthracene (An2Py). The hybrid CsPbBr3@CP-1 composites possess dual emissions: a narrow peak from CsPbBr3 QDs and a broad band from CP-1. Due to the enhanced stability of CsPbBr3 QDs, a white light-emitting diode (LED) was fabricated using CsPbBr3@CP-1 composites. In addition, the hybrid composites shows promising photoelectrical characteristics. Therefore, this work presents a methodology enhancing the stability and optical characteristics of CsPbBr3 QDs, thereby broadening the practical applications of optical QDs in white LEDs and optoelectronic devices. © 2025 Chinese Materials Research Society

关键词： Perovskite

Watt-Level Diode-Pumped Tm:CALGO laser at 2.31 μm

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Watt-Level Diode-Pumped Tm:CALGO Laser at 2.31 μm

CLEO: Science and Innovations in CLEO 2024, CLEO: S and I 2024 - Part of Conference on lasers and Electro-Optics

作者： Yu, Xiaoxu Pan, Zhongben Eremeev, Kirill Loiko, Pavel Chu, Hongwei Pan, Han Braud, Alain Camy, Patrice Giordano, Luidgi Viana, Bruno Griebner, Uwe Petrov, Valentin Li, Dechun School of Information Science and Engineering Key Laboratory of Laser and Infrared System Integration Technology Ministry of Education Shandong University Qingdao266237 China UMR 6252 CEA-CNRS-ENSICAEN Université de Caen 6 Boulevard Maréchal Juin Caen14050 Cedex 4 France Chimie ParisTech PSL University CNRS Institut de Recherche de Chimie Paris 11 rue Pierre et Marie Curie Paris75005 France Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy Max-Born-Str. 2a Berlin12489 Germany

A diode-pumped continuous-wave 1.5 at.% Tm:CALGO laser operating on the 3H4→3H5 transition generated 1.44 W at 2284-2348 nm with a linear laser polarization (σ). The relevant spectroscopic properties of this materia... 详细信息

关键词： Optical pumping

Watt-Level Diode-Pumped Tm:CALGO laser at 2.31 μm

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Watt-Level Diode-Pumped Tm:CALGO Laser at 2.31 μm

2024 Conference on lasers and Electro-Optics, CLEO 2024

作者： Yu, Xiaoxu Pan, Zhongben Eremeev, Kirill Loiko, Pavel Chu, Hongwei Pan, Han Braud, Alain Camy, Patrice Giordano, Luidgi Viana, Bruno Griebner, Uwe Petrov, Valentin Li, Dechun School of Information Science and Engineering Key Laboratory of Laser and Infrared System Integration Technology Ministry of Education Shandong University Qingdao266237 China UMR 6252 CEA CNRS ENSICAEN Université de Caen 6 Boulevard Maréchal Juin Caen14050 Cedex 4 France Chimie ParisTech PSL University CNRS Institut de Recherche de Chimie Paris 11 rue Pierre et Marie Curie Paris75005 France Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy Max-Born-Str. 2a Berlin12489 Germany

ISBN: (纸本)9781957171395

关键词： Electro-optical waveguides laser transitions lasers and electrooptics Semiconductor lasers

In-Plane and Out-of-Plane Anisotropy in the Optical and Dielectric Properties of Yba2cu3o7-x Superconducting Film

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SSRN 2024年

作者： Wang, Yueming Sun, Weixuan Zhao, Minglin Li, Yongfu Wei, Mingyang Jin, Kui Li, Qian Zhou, Xiang'an Ha, Yating Lian, Jie School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and Application Shandong University Qingdao266237 China Center for Optics Research and Engineering Key Laboratory of Laser & Infrared System Ministry of Education Shandong University Qingdao266237 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China School of Science Jiangsu University of Science and Technology Zhenjiang212003 China

YBa2Cu3O7-x (YBCO) is a crucial aspect of research in the field of superconducting applications, where its high anisotropy is generally undesirable in strong power transmission. However, from a dialectical perspective, a thorough investigation of material anisotropy can offer an additional degree of freedom to tune potential properties and design innovative devices. This work employed pulsed laser deposition to fabricate a high-quality YBCO thin film (Tc = 89K) and used the Mueller matrix spectroscopic ellipsometer (MMSE) to determine the complete dielectric tensor of the YBCO film across the ultraviolet to near-infrared spectrum (245-1000nm), enabling a comprehensive, quantitative study of the optical anisotropy of YBCO. It provided optical constants and dielectric function spectra for different axes. We found that YBCO exhibits birefringence and dichroism both in-plane and out-of-plane. By combining standard critical point (SCP) analysis and first-principles calculations, we identified specific interband transitions related to SCP in the YBCO dielectric spectra, revealing the physical essence of anisotropic optical transitions from a quantum mechanical standpoint. Temperature-dependent studies of the transitions and optical constants were conducted, highlighting the significant potential of YBCO for optical device applications. The work also holds relevance for understanding the origins of copper-based high-temperature superconductivity. © 2024, The Authors. All rights reserved.

关键词： Barium compounds

Proton Exchange-Enhanced Surface Activated Bonding for Facile Fabrication of Monolithic Lithium Niobate Microfluidic Chips

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SSRN 2024年

作者： Du, Yu Pang, Zirui Zou, Yuanshu Zhu, Bingxuan Liu, Linjie Zhang, Xuming Wang, Chenxi State Key Laboratory of Precision Welding Joining of Materials and Structures Harbin Institute of Technology Harbin150001 China Photonics Research Institute Department of Applied Physics The Hong Kong Polytechnic University Hong Kong Key Laboratory of Laser & Infrared System Ministry of Education Shandong University Qingdao266237 China Shenzhen518055 China

In the quest to enhance the functionality and efficiency of lab-on-a-chip systems, integrating diverse physical phenomena such as acoustics, optics, and electronics into a single platform has emerged as a pivotal strategy. Lithium niobate (LiNbO3, or LN) stands out for its exceptional piezoelectric and electro-optic properties, making it an ideal candidate for such integrated systems. However, the full exploitation of LN in microfluidic applications has been hindered by the complex challenges associated with its fabrication. Addressing this gap, our research introduces a facile fabrication method for creating monolithic LN microfluidic chips. By employing a proton exchange-assisted surface-activated bonding technique, we achieve high-strength, flawless bonding at lower temperatures, overcoming the traditional barriers of LN machining. This method eliminates the chemical stability of LN by removing lithium ions and significantly enriches the surface with functional groups, leading to a bonding strength exceeding 10 MPa after annealing at 150°C. Additionally, we have optimized an argon plasma etching process to ensure the creation of smooth LN channels at room temperature. The development of a fully integrated LN chip through this approach demonstrates superior performance, especially in surface acoustic wave (SAW) applications, compared to conventional PDMS/LN hybrids. This breakthrough not only realizes the fabrication process of LN microfluidic devices but also opens new avenues for the advancement of integrated microsystems across various scientific and technological domains. © 2024, The Authors. All rights reserved.

关键词： Microfluidic chips

Evolution of Multiple Pulses and Pump Hysteresis Phenomenon in a Passively Mode-Locked Er-Doped Fiber laser Based on an Sb2S3-PVA Saturable Absorber

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SSRN 2023年

作者： Hu, Qiongyu Yang, Kejian Li, Ming Li, Ping Zhao, Haoxu Zhang, Bin Liu, Jing Yang, Yongming Chen, Xiaohan Center for Optics Research and Engineering Key Laboratory of Laser & Infrared System Ministry of Education Shandong University Shandong Qingdao266237 China Institute of Novel Semiconductors State Key Laboratory of Crystal Materials Shandong University Jinan250100 China School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and Application Shandong University Shandong Qingdao266237 China

The evolution of multiple pulses and the pump hysteresis phenomenon were observed in a passively mode-locked Er-doped fiber laser using an Sb2S3-PVA saturable absorber. As the pump power was increased, the generations of onefold, twofold, and threefold pulses were meticulously documented. When the pump power was decreased, the evolution of fivefold and sixfold pulses was carefully recorded, accompanied by a clear pump hysteresis phenomenon. A thorough analysis was conducted to examine and reveal the inversely proportional relationship between the RF spectrum modulation periods and the total pulse intervals of the multi-pulse bunches including from onefold to sixfold pulses. © 2023, The Authors. All rights reserved.

关键词： Hysteresis