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oe1(光电查) - 科学论文

52 条数据
?? 中文(中国)
  • Direct Amplification of High Energy Pulsed Laser in Fiber-Single Crystal Fiber with High Average Power

    摘要: A laser master oscillator power ampli?er (MOPA) system consisting of a ?ber ampli?er and a two-stage Yb:YAG single crystal ?ber (SCF) is experimentally studied. The nonlinear stimulated Raman scattering (SRS) is avoided by limiting the output power of the ?ber preampli?er to 600 mW. Due to the bene?t from the low nonlinearity and high ampli?cation gain of the SCF, a laser pulse duration of 16.95 ps and a high average power of 41.7 W at a repetition rate of 250 kHz are obtained by using a two-stage polarization controlled double-pass ampli?cation of Yb:YAG SCF, corresponding to an output energy of 166.8 μJ and a peak power of 9.84 MW, respectively. The polarization controlled SCF ampli?cation scheme achieved a gain as high as more than 69 times. During the ampli?cation, the spectra gain narrowing e?ect and the polarization controlled four-pass ampli?cation setup are also studied. The laser spectrum is narrowed from over 10 nm to less than 3 nm, and the pulse width is also compressed to hundreds of femtosecond by dechirping the laser pulse. This compact-sized, cost-e?ective laser source can be used in laser micromachining, or as the seeder source for generating much higher power and energy laser for scienti?c research. For some applications which need femtosecond laser, this laser source can also be compressed to femtosecond regime.

    关键词: ytterbium doped fiber amplifier,high-energy ultrashort laser amplification,single crystal fiber

    更新于2025-11-28 14:23:57

  • Solvent-Dependent Sensitization of Ytterbium and Neodymium via an Intramolecular Excimer

    摘要: We report the synthesis of a di(1-pyrenyl)-phosphoryl acetophenone ligand containing two pyrenyl moieties linked by a single phosphorus atom. The ligand exhibits solvent-dependent emission: in nonpolar solvents, typical monomeric pyrene emission is observed, whereas in polar solvents, an additional broad and structureless emission appears. The emission in polar solvents is concentration independent and is attributed to the emission of an intramolecular excimer. The coordination of the di(1-pyrenyl)phosphoryl acetophenone ligand as well as the corresponding deprotonated anionic di(1-pyrenyl)phosphoryl acetophenonate ligand was studied with the near-infrared emitting lanthanides, neodymium and ytterbium. Solvent-dependent sensitization of both lanthanides was observed and correlates with the presence of the excimer emission. Sensitization of ytterbium is more efficient than neodymium, and the overall quantum yields were found to be 12.8 and 1.9% for ytterbium and neodymium, respectively.

    关键词: solvent-dependent emission,quantum yields,ytterbium,neodymium,intramolecular excimer,lanthanides

    更新于2025-11-14 15:24:45

  • Compact Transportable Optical Standard Based on a Single 171Yb+ Ion (“YBIS” Project)

    摘要: The schematic diagram of the compact transportable optical frequency standard based on the quadrupole transition in a single 171Yb+ ion with a relative instability at the level of 5 · 10?16, less than 1 m3 in volume and less than 300 kg in weight is presented. The ionic trap and laser systems are described. Trapping and laser cooling of the 174Yb+ ion are experimentally demonstrated.

    关键词: ytterbium ion,transportable frequency standard,optical clock

    更新于2025-09-23 15:23:52

  • Defect analysis of TiO2 doped with ytterbium and nitrogen by ab initio calculations

    摘要: Different defects are studied in the network of anatase TiO2 to improve the utilization of the material for photoelectrochemical applications. With the ab initio calculations, defect-induced TiO2 models with different doping concentrations and oxidation states of Yb and N dopants are studied. Oxygen-deficient systems are modeled, and the interaction of oxygen vacancy with the Yb and N dopant in the bulk of TiO2 is elucidated. Yb 4f states are coupled with the O 2p states reducing the band gap and shifting the absorption edge of the TiO2 toward visible regime. Increasing Yb doping concentration reduced the band gap, and the 2.08% Yb doping concentration is considered as an optimal Yb doping. Comparing the band structures of mono-doped and codoped samples, Yb, N codoping reduced the band gap while creating isolated states in the forbidden region. Compensated and non-compensated systems of Yb- and/or N-doped TiO2 models are studied. Charge compensation in Yb, N-codoped TiO2 stabilized the system, reduced the band gap without having isolated states and provided broader absorption band. The Ti16?xYbxNyO31?y, x = 2, y = 1, model provided minimum structure modification with the suitable band structure for photoelectrochemical applications explaining the experimental results for the synergistic effect of Yb, N codoping in TiO2.

    关键词: Doping concentration,Point defects,Charge compensation,Ytterbium

    更新于2025-09-23 15:23:52

  • Research on photo-radiation darkening performance of ytterbium-doped silica fibers for space applications

    摘要: Yb3+/Al3+-doped and Yb3+/Al3+/P5+-doped silica fibers with almost identical Yb3+ doping concentrations were prepared using modified chemical vapor deposition methods. A harsh experimental environment for simultaneous photo-darkening (PD) and radio-darkening (RD) of an ytterbium-doped silica fiber (YDF) was established. The RD, PD, and photo–radio-darkening (PRD) of the YDF were characterized at two dose rates of 0.1 rad(Si)/s and 1 rad(Si)/s. The laser performances before and after the darkening process were tested under 974-nm pumping. The results demonstrated that the PD largely dominated the PRD kinetics of the YDF at a low dose rate (e.g., that in space) and that the PRD was not a superposition of RD and PD owing to the pump light bleaching if the induced loss was larger than the PD equilibrium level. The induced loss and defect types were investigated through absorption spectra and electron paramagnetic resonance. The results revealed that the P doping could enhance the PD, RD, and PRD resistances by inhibiting the formation of aluminum–oxygen hole centers.

    关键词: photo-radio darkening,radio-darkening,photodarkening,defects in silica glass,ytterbium doped silica fiber

    更新于2025-09-23 15:23:52

  • Optimization of a supercontinuum source based on tapered ordinary fibers

    摘要: In this paper the generation of visible spectrum via optimized supercontinuum generation (SCG) in tapered ordinary fibers by ultrashort laser pulses is presented. The tunability of the visible part of the spectra is achieved by changing the pump pulse duration during operation. The optimization of the SCG is carried out by the investigation of the taper geometry with the emphasis on the downtapering section length. Its increase is found to be correlated to higher intensity in the visible part of the spectra. This is further supported by the results on spectra evolution before it enters the taper waist where an important transfer of the pump power to the shorter wavelengths is found.

    关键词: fiber lasers,ytterbium-doped fiber amplifiers,supercontinuum generation

    更新于2025-09-23 15:23:52

  • Novel Cyanoarylporphyrazines with Triazole Groups at the Macrocycle Periphery as Potential Sensibilizers of Photodynamic Therapy and Optical Probes of Intracellular Viscosity

    摘要: Novel fluorescent dyes of the cyanoarylporphyrazine series containing peripheral triazole groups have been synthesized. Their photophysical properties and the local viscosity effect on the fluorescence have been studied. The experiments with cell cultures have revealed rapid accumulation of the dyes in the cells cytoplasm. Photo- and dark cytotoxicity of the compounds have been evaluated by means of the MTT test.

    关键词: porphyrazines,template synthesis,optical probes of intracellular viscosity,ytterbium complexes,photosensibilizers

    更新于2025-09-23 15:22:29

  • On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals

    摘要: Rare earth (RE3+) doped inorganic CsPbX3 (X=Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy-conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for photoluminescence quantum yields over 100% (T. J. Milstein, et al., Nano Letters 2018, 18, 3792). In the present work, based on cubic phase of inorganic perovskite, we seek atom-level-insight into the basic mechanisms behind these observations in order to boost the further development of RE3+ doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of step-wise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with 'right-angle' Yb3+-VPb-Yb3+ couple are most likely to form in Yb3+-doped CsPbCl3. Associated with this 'right-angle' couple, the 'right-angle' Pb atom with trapped excited states would localize the photogenerated electrons and could act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.

    关键词: Quantum cutting,Ytterbium-Doped inorganic perovskite,density function theory (DFT)

    更新于2025-09-23 15:22:29

  • Nonlinear multimodal interference for ytterbium-doped all-fiber mode-locking noise-like pulse generation

    摘要: This work demonstrates the generation of the noise-like pulse (NLP) in an all-normal-dispersion passively mode-locked ytterbium-doped ring laser cavity with nonlinear multimodal interference as an equivalent all-fiber saturable absorber, for the first time to the best of our knowledge. Depending on the appropriate optimization of the intra-cavity birefringence and reasonable control of the curving curvature of the multimode fiber, self-started NLP operation can be built and maintained within a wide pump range. Additionally, the effect of the multimode fiber length on the NLP mode-locking performance and the generation of the high power NLP have also been experimentally studied.

    关键词: ytterbium-doped fiber,all-fiber laser,nonlinear multimodal interference,noise-like pulse,mode-locking

    更新于2025-09-23 15:22:29

  • Single-mode large-mode-area Er–Yb fibers with core based on phosphorosilicate glass highly doped with fluorine

    摘要: Single-mode Er–Yb fibers with the core based on a phosphorosilicate glass matrix (up to 6.5 mol.% P2O5) highly doped with fluorine (up to 0.9 wt.%) were fabricated using an all-gas-phase modified chemical vapor deposition method. The core numerical aperture was in the range of 0.07–0.08 relative to the pure silica, which allowed us to increase the single-mode core diameter up to 20 μm. The slope efficiency in lasers based on the fabricated fibers reached 34% relative to the launched pump power.

    关键词: fiber lasers,optical fibers,erbium–ytterbium fibers,erbium-doped fiber amplifiers

    更新于2025-09-23 15:22:29