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Chinese Physics B 2010年第5期19卷 342-346页

作者：王河林王承冷雨欣徐至展候蓝田 State Key Laboratory of High Field laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences institute of infrared Fiber and Sensor Technology School of Information Technology and EngineeringYanshan University

We report on the generation of a high energy and long pulse for pumping optical parametric chirped-pulse amplification （OPCPA） by a high-birefringence photonic crystal fibre （HB-PCF） and a laser-diode-pumped regenerative chirped pulse amplifier. Using the femtosecond pump pulse centred at 815 nm, a 1064 nm soliton pulse is produced in the HB-PCF. After injecting it into an Nd：YAG regenerative amplifier with the glass etalons, a narrow-band amplified pulse with an energy of -4 mJ and a duration of 235 ps is achieved at a repetition rate of 10 Hz, which is suitable for being used as a pump source in the 800 nm OPCPA system.

关键词： high-birefringence photonic crystal fibre high energy broad pulse regenerative amplification

Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using MAX phase Cr2TiAlC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： Ahmed Shakir AL-HITI Hiba HASSAN Department of Electrical Engineering Faculty of Engineering University of Anbar Department of laser and Optoelectronics Engineering University of Technology-Iraq

We demonstrated a new type of MAX phase material, chromium titanium aluminum carbide（Cr2TiAlC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（EDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the embedding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（SA） film demonstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm and 1 560.19 nm, respectively. The Q-switching pulse duration could be varied from 2.46 μs to 770 ns, while the repetition rate varied from 92.76 kHz to 106.6 kHz with an increasing input pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： Saturable absorbers

laser beam induced current microscopy and photocurrent mapping for junction characterization of infrared photodetectors

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Science China(Physics,Mechanics & Astronomy) 2015年第2期58卷 1-13页

作者： QIU WeiCheng HU WeiDa National Laboratory for infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences

For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LBIC microscopy, also generally called photocurrent mapping(PC mapping), can provide spatially resolved information about local electrical properties and p-n junction formation in photovoltaic infrared(including visible light) photodetectors from which it is possible to extract material and device parameters such as junction area, junction depth, diffusion length, leakage current position and minority carrier diffusion length etc. This paper presents a comprehensive review of research background, operating principle, fundamental issues, and applications of LBIC or PC mapping.

关键词： laser beam induced current photocurrent mapping focal plane array photocurrent infrared photodetector

Long Gap Discharge Guiding Experiments Using Strongly and Weakly Ionized Plasma Channels for laser Triggered Lightning

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Plasma Science and Technology 2007年第6期9卷 740-742页

作者： Y.SHIMADA M.YAMAURA C.YAMANAKA institute for laser Technology OsakaJapan

A study to generate longer plasma channel was conucted to improve probability of triggered lightning. To generate the long laser plasma channel, a strongly and a weakly ionized plasma channels were used in series, a scheme called hybrid method. The strongly and the weakly ionized plasma channels were used for triggering an electrical leader and guiding the leader. The electrical leader propagated through the weakly ionized plasma. Then main discharge occurred between the electrodes. It is found that the streamer was accelerated with both the increase in the plasma density and the increase in an ambient electric field close to the plane electrode.

关键词： laser plasma channel lightning velocity of streamer

Comparative chemical sensor for detection of chromium(Ⅵ) in aqueous solution

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Optoelectronics Letters 2025年第1期21卷 21-27页

作者： Sura H.AL-REKABI A.A.ALWAHIB Electrical Technique Department Al Suwayrah Technical Institute Middle Technical University laser and Optoelectronics Department University of Technology-Iraq

A process for purifying aqueous solutions containing heavy and toxic metals such as chromium（Cr） has been investigated. One of the extremely harmful pollutants in rivers and seawater is the heavy metal ions due to their direct impacts on human, animals and plants are hexavalent Cr（Ⅵ）. Consequently, highly sensitive sensor to detect Cr is essential. Surface plasmon resonance（SPR） technique has attracted huge research interest in detecting heavy metals specifically. In this study, three types of prism-based SPR sensor, gold（Au）/silver（Ag）, Au/polyaniline（PANI） and Au/titanium dioxide（TiO2） nanostructured films, are investigated as potential sensing material to detect the presence of Cr（Ⅵ） ions in water. The base Au layer with thickness of 48.3 nm is deposited on a glass slide for all sensors. For Au/Ag, Au/PANI nanofibers and Au/TiO2sensor films, the Cr（Ⅵ） concentration is varied from 1 ppm to 15 ppm with sensitivity of 0.270 °ppm-1, 0.082 °ppm-1and 0.039 °ppm-1, respectively. Based on these results, the Au/PANI nanofibers are the most sensitive to Cr（Ⅵ） among the tested sensing materials.

关键词： Titanium dioxide

Microstructure and Mechanical Properties of Galvanized Steel/AA6061 Joints by laser Fusion Brazing Welding

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Acta Metallurgica Sinica(English Letters) 2014年第4期27卷 670-676页

作者： Junxia L Wuxiong Yang Shikai Wu Xudong Zhao Rongshi Xiao institute of laser Engineering Beijing University of Technology

laser fusion brazing welding was *** steel/AA6061 lapped joint was obtained by laser fusion brazing welding technique using the laser-induced aluminium molten pool spreading and wetting the solid steel *** joint interface was formed using the rectangular laser beam coupled with the synchronous powder *** result showed that the tiny structure with the composition of a-Al and Al–Si eutectic was formed in the weld close to the Al *** close to the steel side,a layer of compact Fe–Al–Si intermetallics,including the Al-rich FeAl3,Fe2Al5 phases and Al–Fe–Si s1 phase,was generated with the thickness of about 10–20 *** tensile shows the brittlefractured characteristic along to the seam/steel interface with the maximum yield strength of 152.5 MPa due to the existence of hardening phases s1 and Al–Fe intermetallics.

关键词： Galvanized steel Aluminium alloy laser welding Interface Microstructural characterization Mechanical property

Effect of scanning speeds on electrochemical corrosion resistance of laser cladding TC4 alloy

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Chinese Physics B 2019年第2期28卷 383-390页

作者： Xiaotian Feng Jianbo Lei Hong Gu Shengfeng Zhou laser Technology institute Tianjin Polytechnic University

In order to study the effect of scanning speed on the electrochemical corrosion resistance of laser cladding TC4 alloy in artificial seawater, the x-ray diffraction analysis, microstructure of cross-section, microhardness variation, and impedance spectrum have been studied in comparison with the TC4 titanium alloy. The results show that the main phase of cladding coating is α-Ti, and the change of scanning speed has no obvious effect on it; therefore, the supersaturated α-Ti solid solution is formed, and the acicular α martensite is obtained. As the scanning speed increases, the microstructure of cladding coating is orthogonal basket-weave, the crystal surface spacing decreases, and the average microhardness of laser cladding TC4 alloy slightly increases. When the scanning speed increases to 10 mm/s, the microhardness is about 14.71%higher than that of the substrate, and the electrochemical corrosion resistance of laser cladding TC4 alloy is also improved,which is about 2.48 times more than the substrate. Grain refinement has a great effect on enhancing the anti-electrochemical corrosion.

关键词： laser cladding TC4 alloy grain refinement electrochemical corrosion

Photobiomodulation:a novel approach to promote trans-differentiation of adipose-derived stem cells into neuronal-like cells

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Neural Regeneration Research 2025年第2期20卷 598-608页

作者： Daniella Da Silva Madeleen Jansen van Rensburg Anine Crous Heidi Abrahamse laser Research Centre Faculty of Health SciencesUniversity of JohannesburgDoornfonteinJohannesburgSouth Africa

Photobiomodulation,originally used red and near-infrared lasers,can alter cellular *** has been demonstrated that the visible spectrum at 451-540 nm does not necessarily increase cell proliferation,near-infrared light promotes adipose stem cell proliferation and affects adipose stem cell migration,which is necessary for the cells homing to the site of *** this in vitro study,we explored the potential of adipose-derived stem cells to differentiate into neurons for future translational regenerative treatments in neurodegenerative disorders and brain *** investigated the effects of various biological and chemical inducers on trans-differentiation and evaluated the impact of photobiomodulation using 825 nm near-infrared and 525 nm green laser light at 5 J/*** adipose-derived stem cells can be used in autologous grafting and photobiomodulation has been shown to have biostimulatory *** findings reveal that adipose-derived stem cells can indeed trans-differentiate into neuronal cells when exposed to inducers,with pre-induced cells exhibiting higher rates of proliferation and trans-differentiation compared with the control ***,green laser light stimulation led to notable morphological changes indicative of enhanced trans-differentiation,while near-infrared photobiomodulation notably increased the expression of neuronal *** biochemical analysis and enzyme-linked immunosorbent assays,we observed marked improvements in viability,proliferation,membrane permeability,and mitochondrial membrane potential,as well as increased protein levels of neuron-specific enolase and ciliary neurotrophic ***,our results demonstrate the efficacy of photobiomodulation in enhancing the trans-differentiation ability of adipose-derived stem cells,offering promising prospects for their use in regenerative medicine for neurodegenerative disorders and brain injuries.

关键词： differentiation inducers green photobiomodulation immortalized adipose-derived stem cell near-infrared photobiomodulation neurodegenerative disease neurogenesis photobiomodulation trans-differentiation

A 980 nm Yb-doped single-mode fibre laser with 946 nm Nd:YAG laser as pump source

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Chinese Physics B 2010年第7期19卷 302-307页

作者：李平雪邹淑珍张雪霞李港 institute of laser Engineering Beijing University of Technology

Based on rate equations, this paper gives expressions of the output power, the pump power threshold, the slope efficiency, the fibre optimal length and the laser gain of a quasi-three-level Yb-doped fibre laser. The gain relationship between quasi-three-level system and four-level system is also given, which provides a theoretical basis for suppressing the four-level transmissions. In the experiment, we adopt the backward pumping configuration and use a linear cavity. The Yb-doped fibre laser has an output power of 372 mW of single-mode laser emission at 980 nm with a slope efficiency of 21.2% when the fibre length is 29.5 cm close to an optimal fibre length in theory. The experimental results accord well with the theoretical analyses.

关键词： quasi-three-level Yb-doped fibre 980 nm laser

Dendritic Boundary Corrosion of AA2198 Weld Using Fiber laser Welding with Al–Cu Filler Wire

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Acta Metallurgica Sinica(English Letters) 2018年第7期31卷 735-741页

作者： Jun-Xia Lu Ling Chang Shi-Kai Wu Shi-Kun Yin institute of laser Engineering Beijing University of Technology

The microstructures and corrosion behaviors of AA2198-T851 alloy and weld were analyzed under corrosive conditions. Weld was formed using an innovative fiber laser welding process with AA2319 Al-Cu filler wire. The metallurgic morphology and distribution of the chemical compositions were determined using imaging techniques such as optical micrograph, scanning electron micrograph, high-resolution transmission electron microscopy, energy-dispersive X-ray spectrometry and X-ray diffraction. Corrosion was evaluated using an immersion test and electrochemical impedance spectroscopy in 3.5% NaC1 solution at room temperature. Results indicate that the parent alloy suffered from pitting corrosion during the initial 4-h immersion which was caused by the inhomogeneous distribution of its chemical compo- nents and the different intermetallics formed during the rolling process. The weld experienced dendritic boundary corrosion under the same conditions due to the addition of the Al-Cu filler and rapid solidification during laser welding, which led to the precipitates Cu enrichment along the grain boundary. When a welding joint was immersed in the solution for 5 days, a big crack was observed across the center of the weld. In comparison, there was good corrosion resistance in the heat- affected zone with a compact protective film.

关键词： 2198 Aluminum alloy. Fiber laser welding Dendritic boundary corrosion Al-Cu filler wire