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8篇 您的检索式:作者名="Pengfei Leng"
    题名 作者 年代 出处 被引量
1Near-diffraction-limited linearly polarized narrow-linewidth random fiber laser with record kilowatt output显示文摘In this paper, we propose and experimentally investigate a linearly polarized narrow-linewidth random fiber laser(RFL) operating at 1080 nm and boost the output power to kilowatt level with near-diffraction-limited beam quality using a master oscillation power amplifier. The RFL based on a half-opened cavity, which is composed of a linearly polarized narrow-linewidth fiber Bragg grating and a 500 m piece of polarization-maintained Ge-doped fiber, generates a 0.71 W seed laser with an 88 pm full width at half-maximum(FWHM) linewidth and a 22.5 dB polarization extinction ratio(PER) for power scaling. A two-stage fiber amplifier enhances the seed laser to the maximal 1.01 k W with a PER value of 17 dB and a beam quality of M_x^2=1.15 and M_y^2=1.13. No stimulated Brillouin scattering effect is observed at the ultimate power level, and the FWHM linewidth of the amplified random laser broadens linearly as a function of the output power with a coefficient of about 0.1237 pm∕W.To the best of our knowledge, this is the first demonstration of a linearly polarized narrow-linewidth RFL with even kilowatt-level near-diffraction-limited output, and further performance scaling is ongoing.JIANGMING XU LONG HUANG MAN JIANG JUN YE PENGFEI MA JINYONG LENG JIAN WU HANWEI ZHANG PU ZHOU 2017Photonics Research2017,5,4:20
2High power all-fiberized and narrow-bandwidth MOPA system by tandem pumping strategy for thermally induced mode instability suppression显示文摘An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability(TMI) suppression. The stimulated Brillouin scattering(SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ~0.025, 0.17 and ~0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3times. The beam quality(M~2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the influence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering(SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multidetrimental effects(SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth fiber amplifiers.Pengfei Ma Hu Xiao Daren Meng Wei Liu Rumao Tao Jinyong Leng Yanxing Ma Rongtao Su Pu Zhou Zejin Liu 2018High Power Laser Science and Engineering2018,6,4:9
3All-fiberized and narrow-linewidth 5 kW power-level fiber amplifier based on a bidirectional pumping configuration显示文摘In this paper,an all-fiberized and narrow-linewidth 5 kW power-level fiber amplifier is presented.The laser is achieved based on the master oscillator power amplification configuration,in which the phase-modulated single-frequency laser is applied as the seed laser and a bidirectional pumping configuration is applied in the power amplifier.The stimulated Brillouin scattering,stimulated Raman scattering,and transverse mode instability effects are all effectively suppressed in the experiment.Consequently,the output power is scaled up to 4.92 kW with a slope efficiency of as high as approximately 80%.The 3-dB spectral width is about 0.59 nm,and the beam quality is measured to be M^(2)~1.22 at maximum output power.Furthermore,we have also conducted a detailed spectral analysis on the spectral width of the signal laser,which reveals that the spectral wing broadening phenomenon could lead to the obvious decrease of the spectral purity at certain output power.Overall,this work could provide a reference for obtaining and optimizing high-power narrow-linewidth fiber lasers.Pengfei Ma Hu Xiao Wei Liu Hanwei Zhang Xiaolin Wang Jinyong Leng Pu Zhou 2021High Power Laser Science and Engineering2021,9,3:9
4Femtosecond mid-IR optical vortex laser based on optical parametric chirped pulse amplification显示文摘A femtosecond mid-infrared optical vortex laser can be used for high harmonic generation to extend cutoff energy to the kilo-electron-volt range with orbital angular momentum,as well as other secondary radiations.For these,we demonstrate a high-energy femtosecond 4μm optical vortex laser based on optical parametric chirped pulse amplification(OPCPA)for the first time.The optical vortex seed is generated from a femtosecond 4μm laser by a silicon spiral phase plate with the topological charge l of 1 before the stretcher.Through using a two-stage collinear OPCPA amplifier,the chirped vortex pulse is amplified to 12.4 m J with 200 nm full width at half-maximum bandwidth.After compression,the vortex laser pulse with 9.53 m J,119 fs can be obtained.Furthermore,the vortex characteristics of the laser beam are investigated and evaluated.This demonstration can scale to generate a higher-peak-power vortex mid-IR laser and pave a new way for high field physics.JUNYU QIAN YUJIE PENG YANYAN LI PENGFEI WANG BEIJIE SHAO ZHE LIU YUXIN LENG RUXIN LI 2020Photonics Research2020,8,3:4
5High-repetition-rate, high-peak-power 1450 nm laser source based on optical parametric chirped pulse amplification显示文摘We present a high-peak-power,near-infrared laser system based on optical parametric chirped pulse amplification pumped by a home-built picosecond pumping laser,which can generate over 40 mJ energy at 1450 nm center wavelength and operate at 100 Hz repetition rate.Subsequently,the chirped laser pulses are compressed down to 60 fs with 26.5 mJ energy,corresponding to a peak power of 0.44 TW. This high-energy,long-wavelength laser source is highly suitable for driving various nonlinear optical phenomena,such as high-order harmonic generation and high-flux coherent extreme ultraviolet/soft X-ray radiation.Pengfei Wang Beijie Shao Hongpeng Su Xinlin Lv Yanyan Li Yujie Peng Yuxin Leng 2019High Power Laser Science and Engineering2019,7,2:2
6Pulse combination and compression in hollow-core fiber for few-cycle intense mid-infrared laser generation显示文摘The generation of high-peak-power,few-cycle mid-infrared(MIR)pulses using coherent beam combination and nonlinear pulse compression techniques simultaneously is demonstrated.The two pulses,with identical pulse energy of 2.8 mJ and pulse duration of 160 fs,are coherently combined at the input end of a krypton-filled hollow-core fiber(HCF),and then the bandwidth of the combined pulse is broadened to near an optical octave due to strong phase modulations,and the temporal width is compressed into a few-cycle regime.Finally,a 2.7 mJ,22.9 fs,20 Hz laser at 4μm can be obtained,and the pulse peak power is greatly enhanced compared with that of conventional single-channel optical parametric chirped pulse-amplification systems.Furthermore,the peak power generated from this system has the prospect of further scaling up through use of more channels of coherent combination,which can pave a way to generate higher peak power ultra-intense MIR pulses for strong-field physics.Junyu Qian Pengfei Wang Yujie Peng Yanyan Li Beijie Shao Hongpeng Su Xinlin Lv Ding Wang Yuxin Leng Ruxin Li 2021Photonics Research2021,9,4:2
7Auxin Binding Protein 1 Reinforces Resistance to Sugarcane Mosaic Virus in Maize显示文摘Pengfei Leng Qing Ji Torben Asp Ursula K. Frei Christina R. Ingvardsen Yongzhong Xing Bruno Studer Margaret Redinbaugh Mark Jones Priyanka Gajjar Sisi Liu Fei Li Guangtang Pan Mingliang Xu Thomas Lǖbberstedt 2017Molecular Plant2017,10,10:2
8Texturing and evaluation of concrete pavement surface:A state-of-the-art review显示文摘Concrete pavement is accompanied by two major functional properties,namely noise emission and friction,which are closely related to pavement surface texture.While several technologies have been developed to mitigate tirepavement noise and improve driving friction by surface texturization,limited information is available to compare the advantages and disadvantages of different surface textures.In this study,a state-of-the-art and state-of-thepractice review is conducted to investigate the noise reduction and friction improvement technologies for concrete pavement surfaces.The commonly used tests for characterizing the surface texture,skid resistance,and noise emission of concrete pavement were first summarized.Then,the texturing methods for both fresh and hardened concrete pavement surfaces were discussed,and the friction,noise emission and durability performances of various surface textures were compared.It is found that the next generation concrete surface(NGCS)texture generally provides the best noise emission performance and excellent friction properties.The exposed aggregate concrete(EAC)and optimized diamond grinding textures are also promising alternatives.Lastly,the technical parameters for the application of both diamond grinding and diamond grinding&grooving textures were recommended based on the authors'research and practical experience in Germany and the US.This study offers a convenient reference to the pavement researchers and engineers who seek to quickly understand relevant knowledge and choose the most appropriate surface textures for concrete pavements.Zhen Leng Zepeng Fan Pengfei Liu Jonas Kollmann Markus Oeser Dawei Wang Xi Jiang 2023Journal of Road Engineering2023,3,3:0
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