- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Femtosecond Red and Near-Infrared Lasers Due to Cascaded-Raman-Assisted Four-Wave Mixing in a Nonlinear Yb-Doped Fiber Amplifier
摘要： We demonstrated a straightforward approach to generate red and near-infrared laser emissions by a Raman-assisted four wave mixing (FWM) process in a nonlinear Yb-doped fiber amplifier, delivering 342 fs pulses of 241 nJ at 864 nm, 834 fs pulses of 21 nJ at 751 nm, and 1.9 ps pulses of 3.8 μJ at 1030 nm. A pair of gratings was employed as the pre-compressor to promote the intensity of the fundamental wave in the main amplifier. Multiple wavelengths from 751 to 1273 nm resulted due to cascaded-Raman-assisted FWM. The pre-compression also underlay the achievement of 25.1, 701, and 2000 kW peak power for the red (751 nm), near-infrared (864 nm), and fundamental (1030 nm) components respectively, which restrained the gain narrowing effect during the amplification. It finally led to shorter pulse duration under increased power.
关键词： femtosecond fiber laser,four-wave mixing,fiber amplifier
更新于2025-09-23 15:19:57
-
Femtosecond Laser Additive Manufacturing of Multi-Material Layered Structures
摘要： Laser additive manufacturing (LAM) of a multi-material multi-layer structure was investigated using femtosecond fiber lasers. A thin layer of yttria-stabilized zirconia (YSZ) and a Ni–YSZ layer were additively manufactured to form the electrolyte and anode support of a solid oxide fuel cell (SOFC). A lanthanum strontium manganite (LSM) layer was then added to form a basic three layer cell. This single step process eliminates the need for binders and post treatment. Parameters including laser power, scan speed, scan pattern, and hatching space were systematically evaluated to obtain optimal density and porosity. This is the first report to build a complete and functional fuel cell by using the LAM approach.
关键词： femtosecond laser,laser,fuel cell,additive manufacturing,fiber laser,YSZ,SOFC
更新于2025-09-23 15:19:57
-
Temperature changes during laser lithotripsy with Ho:YAG laser and novel Tm-fiber laser: a comparative in-vitro study
摘要： Aim The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. Methods We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 μm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). Results Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL ? 1.9 °C; for Ho:YAG laser ? 2.8 °C at 60 s). Conclusion SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.
关键词： Ho:YAG laser,Laser lithotripsy,Thermal effect,Thulium fiber laser,In-vitro
更新于2025-09-23 15:19:57
-
41.8??W output power, 200??kHz repetition rate ultra-fast laser based on Yb:YAG single crystal fiber(SCF)amplifier
摘要： We demonstrate a high repetition rate, high energy chirped pulse amplification (CPA) system based on single crystal fiber (SCF) amplifier. With home-made all-fiber laser as the seed laser and Yb:YAG rod, SCF as the amplification gain medium, an output power of 61.8 W at 200 kHz repetition rate has been obtained. To the best of our knowledge, this is the highest power based on SCF at hundreds of kHz repetition rate. The measured M2 values are approximately 1.241 in the horizontal and 1.186 in the vertical direction. The spectrum width is 3.8 nm, which support Fourier transform-limited pulse duration of 411 fs. An average power of 41.8 W with pulse duration of 1.5 ps has been obtained after the chirped volume Bragg grating (CVBG) compressor, which will be compressed to hundreds of fs with accurate chirp compensation.
关键词： Ultrafast laser,SCF,Fiber laser,CPA
更新于2025-09-23 15:19:57
-
Correlation between plume fluctuation and keyhole dynamics during fiber laser keyhole welding
摘要： In order to reveal the fluctuation mechanism of the plume induced during fiber laser keyhole welding, dynamic behaviors of both the plume and the keyhole were simultaneously observed by using the multiple-imaging method. The results show that the fluctuation period of the plume was the same as that of the laser-induced vapor moving down on the keyhole front wall (KFW). The tilt angle of the plume was the largest when the laser-induced vapor was close to the orifice. As the laser-induced vapor moved toward the bottom of the KFW, the tilt angle of the plume decreased gradually. The correlation between the plume fluctuation and the dynamics of the laser-induced vapor on the KFW was not affected by parameters such as welding speed, laser power, and focal length. Further analysis shows that the periodic drilling behavior of the laser spot on the KFW is the main reason for the periodic fluctuation of the plume.
关键词： KFW,plume,fiber laser welding,laser-induced vapor,fluctuation
更新于2025-09-23 15:19:57
-
Features of fused silica ablation by laser induced carbon microplasma
摘要： The features of surface structuring on the transparent material by laser-induced microplasma were studied and the intensity of its microplasma was measured. The formation of micro-relief by a series of nanosecond pulsed laser induced carbon microplasma in confinement mode on the surface of fused silica were investigated and the measured intensity was compared with the features of micro-relief. The dependence of depth of formed relief and track on the laser regime was determined. It is shown that the mechanism of microstructure formation is dependent on multifactor and associated with the ablation on the surface of fused silica by the microplasma, which exists quite long time after the pulses.
关键词： Ablation,Surface structuring,Laser-induced microplasma,Nanosecond pulses,Fiber laser,Fused silica
更新于2025-09-23 15:19:57
-
1.6 Micron Fiber Laser Source for CH <sub/>4</sub> Gas Leak Detection
摘要： We report on the development of a new pulsed fiber laser source at 1645.5 nm, based on stimulated Raman amplification. This laser source is intended to be used in a future lidar system, dedicated to methane gas leak monitoring in the vicinity of industrial facilities. In this paper we discuss reasons for choosing the 1645.5 nm wavelength, and then we present the two-stage amplification architecture of our fiber laser source under development. Recent experimental results and perspectives are drawn.
关键词： Raman amplification,fiber laser,methane gas leak detection,lidar
更新于2025-09-23 15:19:57
-
Zinc-oxide nanoparticle-based saturable absorber deposited by simple evaporation technique for Q-switched fiber laser
摘要： A Q-switched erbium-doped fiber laser (EDFL) incorporating zinc-oxide (ZnO) nanoparticles-based saturable absorber (SA) is proposed and demonstrated. To form the SA, the ZnO nanoparticles, which are originally in the powder form, are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique. By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL, a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW. As the pump power is increased, the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39 μs to 3.65 μs. Additionally, this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW. These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation, which offers the flexibility and easy integration of the SA into a ring laser cavity.
关键词： saturable absorber,zinc oxide,fiber laser,Q-switched
更新于2025-09-23 15:19:57
-
[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Knowledge-aided Color Loading Sparse Recovery STAP Algorithm
摘要： We numerically study the dynamics of supercontinuum generation (SCG) for a variety of possible combinations of photonic crystal fibers (PCFs) and ultrafast fiber laser pulses that the current technologies offer. Three types of PCFs typically used in SCG and four representative types of ultrafast fiber laser pulses are considered for this combinatorial study. We numerically model and qualitatively discuss the nonlinear evolution of the pulses for their whole 12 combinatorial cases. We also quantitatively analyze their output spectra and organize a performance chart for them in terms of spectral bandwidth, flatness, and degree of spectral coherence. Finally, we suggest the most viable combinations among the given PCFs and ultrafast fiber laser pulses in order for generating a target supercontinuum spectrum for various specific cases.
关键词： Optical fiber laser,nonlinear optics,supercontinuum generation,ultrashort pulse
更新于2025-09-23 15:19:57
-
Wave plate-dependent lasing regimes transitions in an all-normal-dispersion fiber laser mode-locked by nonlinear polarization rotation
摘要： We address the transitions between three different working regimes of an all-normal-dispersion pulsed fiber laser, mode-locked by nonlinear polarization rotation (NPR). In particular, we investigate numerically the dynamics and study in details the transitions induced by solely rotating the cavity wave plates. We analyze the phemomenon by putting forward a model for all-normal-dispersion NPR-moded-locked fiber laser, based on the coupled Ginzburg-Landau equations and Jones matrix. Numerical results show that depending on the values of the cavity parameters, the transitions between the dissipative soliton regime and amplifier similariton one, or the transition between the dissipative soliton regime and the splitting pulse one may be realized by simply rotating the cavity wave plates. We found that the transitions are intrinsically related to the NPR mode-locking mechanism by explicitly evaluating the polarization states across the pulse at different locations of the cavity. Our numerical results are in very good agreement with experimental results reported in the relevant literature, and provide evidence that besides gain saturation and spectral filtering, the orientations of wave plates may be exploited as a suitable degree of freedom to obtain the desired pulse regimes in all-normal-dispersion fiber lasers.
关键词： Amplifier similariton,Splitting pulse,All-normal-dispersion fiber laser,Dissipative soliton,Nonlinear polarization rotation
更新于2025-09-23 15:19:57