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High-power MoTe_2-based passively Q-switched erbium-doped fiber laser

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Chinese Optics Letters 2018年第2期16卷 59-63页

作者： Mengli Liu Wenjun Liu Peiguang Yan shaobo fang Hao Teng Zhiyi Wei State Key Laboratory of Information Photonics and Optical Communications School of Science Beijing University of Posts and Telecommunications Beijing 100876 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Shenzhen Key Laboratory of Laser Engineering College of Optoelectronic Engineering Shenzhen University Shenzhen 518060 China

Materials in the transition metal dichalcogenide family, including WS2, MoS2, WSe2, and MoSe2, etc., have captured a substantial amount of attention due to their remarkable nonlinearities and optoelectronic *** with WS2 and MoS2, the monolayered MoTe2 owns a smaller direct bandgap of 1.1 eV. It is beneficial for the applications in broadband absorption. In this letter, using the magnetron sputtering technique, MoTe2 is deposited on the surface of the tapered fiber to be assembled into the saturable absorber. We first implement the MoTe2-based Q-switched fiber laser operating at the wavelength of 1559 nm. The minimum pulse duration and signal-to-noise ratio are 677 ns and 63 dB, respectively. Moreover, the output power of 25 mW is impressive compared with previous work. We believe that MoTe2 is a promising 2D material for ultrafast photonic devices in the high-power Q-switched fiber lasers.

关键词： High-power MoTe2-based passively Q-switched erbium-doped fiber laser

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亚周期超快光场相干合成技术

光学学报 2019年第1期39卷 113-123页

作者：方少波魏志义中国科学院物理研究所北京凝聚态物理国家研究中心北京100190 中国科学院大学北京100049

随着超快激光脉冲宽度不断变窄,进一步产生单周期乃至亚周期的脉冲面临着巨大的技术挑战。通过脉冲载波包络相位精密控制技术相干合成多路超快光场,不仅是目前超快光学的重要前沿内容,也是实现亚周期脉冲极为有效的方案。结合本课题组... 详细信息

随着超快激光脉冲宽度不断变窄,进一步产生单周期乃至亚周期的脉冲面临着巨大的技术挑战。通过脉冲载波包络相位精密控制技术相干合成多路超快光场,不仅是目前超快光学的重要前沿内容,也是实现亚周期脉冲极为有效的方案。结合本课题组近年来在相干合成方面的研究进展,介绍相干合成超快光场的主要技术内容,包括超宽带光谱的产生、色散管理及载波包络相位控制等技术。

关键词：物理光学超快光学超快激光脉冲相干合成亚周期超连续光谱

Nonlinear optical properties of WSe_2 and MoSe_2 films and their applications in passively Q-switched erbium doped fiber lasers

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Photonics Research 2018年第10期6卷 I0017-I0023页

作者： WENJUN LIU MENGLI LIU HAINIAN HAN shaobo fang HAO TENG MING LEI ZHIYI WEI State Key Laboratory of Information Photonics and Optical Communications School of Science Beijing University of Posts and Telecommunications Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Transition metal dichalcogenides(TMDs) are successfully applied in fiber lasers for their photoelectric ***, in previous work, how to improve the modulation depth of TMD-based saturable absorbers(SAs) has been a challenging issue. In this paper, WSe_2 and MoSe_2 SAs are fabricated with the chemical vapor deposition method. Compared with previous experiments, the modulation depths of WSe_2 and MoSe_2 SAs with sandwiched structures are effectively increased to 31.25% and 25.69%, respectively. The all-fiber passively Q-switched erbium doped fiber lasers based on WSe_2 and MoSe_2 SAs are demonstrated. The signal-to-noise ratios of those lasers are measured to be 72 and 57 dB, respectively. Results indicate that the proposed WSe_2 and MoSe_2 SAs are efficient photonic devices to realize stable fiber lasers.

关键词：光电性能激光器通讯技术发展现状

Optical properties and applications for MoS_2-Sb_2Te_3-MoS_2 heterostructure materials

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Photonics Research 2018年第3期6卷 220-227页

作者： WENJUN LIU YA-NAN ZHU MENGLI LIU BO WEN shaobo fang HAO TENG MING LEI LI-MIN LIU ZHIYI WEI State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Beijing Computational Science Research Center Beijing 100193China School of Physics and Nuclear Energy Engineering Beihang UniversityBeijing 100083China

Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of stable high-energy ultrashort pulses requires further boosting of these materials' optical properties, such as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure material with uniformity by employing the magnetron sputtering technique. Heterostructure materials are synthesized with van der Waals heterostructures consisting of MoS_2 and Sb_2Te_3. The bandgap, carrier mobility, and carrier concentration of the MoS_2-Sb_2Te_3-MoS_2 heterostructure materials are calculated theoretically. By using these materials as saturable absorbers(SAs), applications in fiber lasers with Q-switching and mode-locking states are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%and 14.13 J∕cm^2, respectively. Both theoretical and experimental results indicate that MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have large modulation depth, and can resist high power during the generation of ultrashort pulses. The MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have the advantages of low cost, high reliability, and suitability for mass production, and provide a promising solution for the development of 2D-material-based devices with desirable electronic and optoelectronic properties.

关键词： Mo Sb Optical properties and applications for MoS2-Sb2Te3-MoS2 heterostructure materials Te EDF

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冷挤压技术在汽车转向器上的应用

新技术新工艺 2009年第7期 70-71页

作者：唐少波上海采埃孚转向机有限公司上海201821

相比传统机加工方式,冷挤压工艺可以节约材料、降低成本和改善性能。随着国内冷挤压技术的不断提高,在汽车转向器零部件的制造中逐渐开始应用。本文结合转向器中的齿轮、齿条、阀芯、阀套和横拉杆等主要零件,对冷挤压工艺的实际使用情... 详细信息

相比传统机加工方式,冷挤压工艺可以节约材料、降低成本和改善性能。随着国内冷挤压技术的不断提高,在汽车转向器零部件的制造中逐渐开始应用。本文结合转向器中的齿轮、齿条、阀芯、阀套和横拉杆等主要零件,对冷挤压工艺的实际使用情况进行了介绍和阐述。

关键词：汽车转向器冷挤压应用

Sub-10-fs pulse generation from a blue laser-diode-pumped Ti:sapphire oscillator

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Chinese Optics Letters 2020年第7期18卷 60-63页

作者： Han Liu Geyang Wang Jianwang Jiang Wenlong Tian Dacheng Zhang Hainian Han shaobo fang Jiangfeng Zhu Zhiyi Wei School of Physics and Optoelectronic Engineering Xidian UniversityXi’an 710071China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Pulses as short as 8.1 fs were generated from a blue laser-diode-pumped Kerr-lens mode-locked Ti:sapphire oscillator, with an average power of 27 m W and a repetition rate of 120.6 MHz. The full width at half-maximum exceeds 146 nm, benefitting from the dispersion management by a combination of a low-dispersion fused silica prism pair and a series of double-chirped mirrors. To the best of our knowledge, this is the first time to generate sub-10-fs pulses from a laser diode directly pumped Ti:sapphire oscillator.

关键词： diode-pumped lasers titanium mode-locked lasers

Harmonically pump a femtosecond optical parametric oscillator to 1.13 GHz by a femtosecond 515 nm laser

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Chinese Optics Letters 2020年第3期18卷 57-61页

作者： Jiajun Song Xianghao Meng Zhaohua Wang Xianzhi Wang Wenlong Tian Jiangfeng Zhu shaobo fang Hao Teng Zhiyi Wei Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China School of Physics and Optoelectronic Engineering Xidian UniversityXi’an 710071China

We demonstrate a harmonically pumped femtosecond optical parametric oscillator(OPO)laser using a frequency-doubled mode-locked Yb:KGW laser at a repetition rate of 75.5 MHz as the pump *** on a bismuth borate nonlinear crystal,repetition rates up to 1.13 GHz are realized,which is 15 times that of the pump *** signal wavelength is tunable from 700 nm to 887 *** maximum power of the signal is 207 m W at the central wavelength of 750 nm and the shortest pulse duration is 117 fs at 780 *** beam quality(M^2 factor)in the horizontal and vertical directions of the output beam are 1.077 and 1.141,respectively.

关键词： GHz femtosecond laser optical parametric oscillator tunable wavelength

多模态MRI评估宫颈癌缺氧及缺氧治疗的研究进展

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国际医学放射学杂志 2023年第1期46卷 75-79页

作者：段志青方少伯王绍武大连医科大学附属第二医院放射科大连116023

缺氧是宫颈癌的不利因素之一,在评估肿瘤快速生长、转移、放化疗抵抗方面具有重要意义。多种病理机制可导致宫颈癌缺氧。近年来由于MRI具有无创性及可重复测量的优势,在反映缺氧机制、表征缺氧状态及评估缺氧治疗的疗效和预后方面取得... 详细信息

缺氧是宫颈癌的不利因素之一,在评估肿瘤快速生长、转移、放化疗抵抗方面具有重要意义。多种病理机制可导致宫颈癌缺氧。近年来由于MRI具有无创性及可重复测量的优势,在反映缺氧机制、表征缺氧状态及评估缺氧治疗的疗效和预后方面取得了一定进展。就多模态MRI应用于宫颈癌缺氧及缺氧治疗方面的研究进展予以综述。

关键词：宫颈癌缺氧磁共振成像血氧水平依赖组织氧水平依赖动态对比增强扩散加权成像

同方期刊数据库博看期刊评论

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表观扩散系数直方图分析在肿瘤中的应用进展

国际医学放射学杂志 2021年第6期44卷 706-711页

作者：方少伯朱逸峰王绍武(审校) 大连医科大学附属第二医院放射科大连116023

表观扩散系数直方图分析是一种MR影像分析方法,与传统影像分析方法相比具有丰富的描述性参数,有助于评估肿瘤的整体异质性,在肿瘤诊断和治疗中发挥了越来越重要的作用。近年来,ADC直方图分析广泛用于肿瘤研究,特别是在鉴别肿瘤良恶性和... 详细信息

表观扩散系数直方图分析是一种MR影像分析方法,与传统影像分析方法相比具有丰富的描述性参数,有助于评估肿瘤的整体异质性,在肿瘤诊断和治疗中发挥了越来越重要的作用。近年来,ADC直方图分析广泛用于肿瘤研究,特别是在鉴别肿瘤良恶性和评价肿瘤疗效方面。对ADC直方图分析方法及其在肿瘤鉴别诊断、术前预测组织病理学分级、评价疗效及预后方面应用的研究进展作一综述。

关键词：磁共振成像表观扩散系数直方图分析肿瘤