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Low-cost multimode diode-pumped Tm:YAG and Tm:LuAG lasers
摘要： We report a continuous-wave operation of Tm:YAG and Tm:LuAG lasers pumped with a low-cost, multimode AlGaAs laser diode. First, the lifetime and the absorbance behavior of 5 mm, 6% Tm 3+ -doped YAG and LuAG crystals were thoroughly investigated. A low-cost multimode 3W laser diode at 781 nm was then used as a pump source for the Tm 3+ -doped laser systems. Using three different output couplers, up to 636 mW of output power was obtained from Tm:YAG laser, with a slope efficiency of 29% at 2017 nm. The maximum output power was 637 mW in the Tm:LuAG laser, with a slope efficiency of 28% at 2023 nm. The lasing performances showed a decreasing slope efficiency with an increasing level of output coupling, which leads to a high upconversion. Furthermore, using a birefringent filter in the resonators, the laser outputs were tuned from 1942 to 2086 nm in the Tm:YAG resonator and from 1931 to 2107 nm in the Tm:LuAG case.
关键词： diode-pumped lasers,infrared lasers,Tm:LuAG laser,Tm:YAG laser,tunable lasers,solid-state lasers,Lasers
更新于2025-09-11 14:15:04
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Direct Generation of a Laguerre-Gaussian-Mode Optical Vortex Beam in a Single-Frequency Nd:YVO4 Unidirectional Ring Laser
摘要： A single-frequency, unidirectional ring laser with a ?rst order Laguerre-Gaussian (LG01) mode output end-pumped by using a ring-shaped pump beam is reported. This approach has been applied to a diode-pumped Nd:YVO4 laser in a traveling wave resonator con?guration yielding 2.1 W and 1.5 W of single-frequency LG01 mode outputs with helical wavefronts of left- and right-handedness, respectively. Moreover, we show that its wavefront helicity can be switched by changing the lasing direction and frequency. The selection mechanism of the wavefront helicity and the prospects of this approach are discussed.
关键词： Diode-pumped solid state lasers,Single-frequency laser,Optical vortices,Laguerre-Gaussian mode
更新于2025-09-11 14:15:04
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Effect of electron donor and acceptor in dithienopyrrolobenzothiadiazole-based organic dyes for efficient quasi-solid-state dye-sensitized solar cells
摘要： Three new organic dyes H1-3 with dithienopyrrolobenzothiadiazole moiety as the π-bridge have been synthesized and applied in quasi-solid-state dye-sensitized solar cells. The influences of different electron acceptor of the sensitizers on the photo-physical, electrochemical and photovoltaic performances have been studied. The results show that the inserted electron-withdrawing unit benzothiadiazole in the acceptor part can obviously enhance the light-harvesting ability of the dyes. In addition, the introduced benzothiadiazole moiety in acceptor can increase the π-electron distribution in LUMO level, which may facilitate to the photogenergated electrons injection into TiO2 film. The effects of different electron donor on the solar cell performances have been evaluated. The dihexyloxy substituted triphenylamine is better to suppress the intermolecular aggregation and restrain electron recombination. Finally, the quasi-solid-state solar cell sensitized by dye H2 with 1 mM chenodeoxycholic acid as the co-adsorbent obtains a power conversion efficiency of 7.56%, which close to the level of dye N719 (7.66%) under the same condition.
关键词： Benzothiadiazole,Electron donor,Quasi-solid-state dye-sensitized solar cells,Power conversion efficiency,Dithienopyrrolobenzothiadiazole
更新于2025-09-11 14:15:04
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - False Negative And False Positive Free Nanopore Fabrication Via Adaptive Learning Of The Controlled Dielectric Breakdown
摘要： We investigate the current transport characteristics in the electrolyte-dielectric-electrolyte structure commonly used in the in-situ controlled breakdown (CBD) fabrication of solid-state nanopores. It is found that the stochastic breakdown process could lead to fidelity issues of false positives (an incorrect indication of a true nanopore formation) and false negatives (inability to detect initial nanopore formation). Robust and deterministic detection of initial physical breakdown to alleviate false positives and false negatives is critical for precise nanopore size control. To this end, we report a high fidelity moving Z-Score method based CBD fabrication of solid-state nanopore. We demonstrate 100% success rate of realizing the initial nanopore conductance of 3±1 nS (corresponds to the size of 1.7±0.6 nm) regardless of the dielectric membrane characteristics. Our study also elucidates the Joule heating is the dominant mechanism for electric field-based nanopore enlargement. Single DNA molecule sensing using nanopores fabricated by this method was successfully demonstrated. We anticipate the moving Z-Score based CBD method could enable broader access to the solid state nanopore-based single molecule analysis.
关键词： Solid-state nanopore,DNA sensing,controlled breakdown,moving Z-Score
更新于2025-09-11 14:15:04
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Diode-pumped continuous-wave Yb:YAP laser
摘要： High power continuous-wave operation of a diode-pumped Yb:YAP laser was demonstrated. The laser generated >7 W of output power with 22 W of pump power with the slope efficiency of around 70% while maintaining high beam quality. The combination of high thermal conductivity and broad gain bandwidth makes this laser host an attractive candidate for high power CW and ultrashort pulse generation.
关键词： diode-pumped laser,Yb-doped laser crystals,solid-state laser
更新于2025-09-11 14:15:04
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Enhanced Stability of Perovskite Solar Cells Incorporating Dopant‐Free Crystalline Spiro‐OMeTAD Layers by Vacuum Sublimation
摘要： The main handicap still hindering the eventual exploitation of organometal halide perovskite-based solar cells is their poor stability under prolonged illumination, ambient conditions, and increased temperatures. This article shows for the first time the vacuum processing of the most widely used solid-state hole conductor (SSHC), i.e., the Spiro-OMeTAD [2,2′,7,7′-tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9′-spirobifluorene], and how its dopant-free crystalline formation unprecedently improves perovskite solar cell (PSC) stability under continuous illumination by about two orders of magnitude with respect to the solution-processed reference and after annealing in air up to 200 °C. It is demonstrated that the control over the temperature of the samples during the vacuum deposition enhances the crystallinity of the SSHC, obtaining a preferential orientation along the π–π stacking direction. These results may represent a milestone toward the full vacuum processing of hybrid organic halide PSCs as well as light-emitting diodes, with promising impacts on the development of durable devices. The microstructure, purity, and crystallinity of the vacuum sublimated Spiro-OMeTAD layers are fully elucidated by applying an unparalleled set of complementary characterization techniques, including scanning electron microscopy, X-ray diffraction, grazing-incidence small-angle X-ray scattering and grazing-incidence wide-angle X-ray scattering, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy.
关键词： perovskite solar cells,organometal halide perovskites,stability,vacuum deposition,solid state hole conductors,Spiro-OMeTAD
更新于2025-09-11 14:15:04
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Optimization and performance of nitrogen-doped carbon dots as a color conversion layer for white-LED applications
摘要： In this study, green-emitting nitrogen-doped carbon dots (N-CDots) were synthesized and incorporated into drop-cast composite films for use as color conversion layers in a white-LED configuration to generate white light. In order to resolve the red deficiency of this configuration, a commercial red phosphor was integrated into the system. Moreover, the N-CDots were also processed into polymer/N-CDot composite fibers, for which we determined the amount of N-CDots that yielded adequate white-light properties. Finally, we showed that white light with excellent properties could be generated by employing both of the fabricated N-CDot composites either as drop-cast films or composite fibers. Hence, N-CDots provide a promising alternative to inorganic phosphors that are commonly employed in white-LED configurations.
关键词： PVP,nitrogen-doped carbon dots,color conversion layer,electrospinning,white-light generation,white LED,solid-state lighting
更新于2025-09-11 14:15:04
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Photon detection system designs for the Deep Underground Neutrino Experiment
摘要： The Deep Underground Neutrino Experiment (DUNE) will be a premier facility for exploring long-standing questions about the boundaries of the standard model. Acting in concert with the liquid argon time projection chambers underpinning the far detector design, the DUNE photon detection system will capture ultraviolet scintillation light in order to provide valuable timing information for event reconstruction. To maximize the active area while maintaining a small photocathode coverage, the experiment will utilize a design based on plastic light guides coated with a wavelength-shifting compound, along with silicon photomultipliers, to collect and record scintillation light from liquid argon. This report presents recent preliminary performance measurements of this baseline design and several alternative designs which promise signi?cant improvements in sensitivity to low-energy interactions.
关键词： Neutrino detectors,Photon detectors for UV, visible and IR photons (solid-state),Scintillators and scintillating ?bres and light guides,Noble liquid detectors (scintillation, ionization, double-phase)
更新于2025-09-11 14:15:04
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Solid-state emitter embedded in a microcavity under intense excitation: A variational master-equation approach
摘要： In this work, dissipative effects from a phonon bath on the resonance ?uorescence of a solid-state two-level system embedded in a high-quality semiconductor microcavity and driven by an intense laser are investigated. Within the density operator formalism, we derive a variational master equation valid for broader ranges of temperatures, pumping rates, and radiation-matter couplings than previous studies. From the obtained master equation, ?uorescence spectra for various thermal and exciting conditions are numerically calculated and compared to those computed from weak coupling and polaronic master equations, respectively. Our results evidence the breakdown of those rougher approaches under increased temperature and strong pumping.
关键词： solid-state emitter,variational master equation,microcavity,phonon bath,resonance ?uorescence
更新于2025-09-11 14:15:04
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Radical induced cationic frontal twin polymerization of Si-spiro compound in combination with bisphenol-A-diglycidylether
摘要： The radical induced cationic frontal polymerization (RICFP) of the twin monomer with 2,2’-spirobi[4H-1,3,2-benzodioxasiline] combination (SPIRO) in bisphenol-A-diglycidylether (BADGE) has been developed to fabricate nanostructured hybrid material with domain sizes of 2–5 nm. In one reaction step, an interpenetrating network of phenolic resin, SiO2 and the epoxy resin is formed in a very short time period, initiated by UV light. That indicates that both polymerization reactions take place simultaneously. The influence of monomer composition on molecular structure was investigated by means of solid state NMR spectroscopies. The envisaged nanostructure of the resulting organic-inorganic hybrid materials is proven by transmission electron microscopy high-angle annular dark-field scanning (HAADF-STEM). The thermal properties of the hybrid materials are comparable to “state of the art” materials with the advantage that the silica quantity can be adjusted on demand.
关键词： Nanostructured hybrid material,HAADF-STEM,Solid state NMR spectroscopy,Radical induced cationic frontal polymerization,Twin polymerization
更新于2025-09-11 14:15:04