KW-level Yb-doped aluminophosphosilicate (Yb-APS) large-mode-area fiber was fabricated by chelate precursor doping technique. The fiber shown excellent laser stability for over 10 hours at 900 W with power fluctuation of 2.2%.
Using chemical solution spin-coating we grew Pb(Zr0.52Ti0.48)O3 films of different thicknesses on highly dense CoFe2O4 ceramics. X-ray diffraction revealed no other phases except Pb(Zr0.52Ti0.48)O3 and CoFe2O4. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr0.52Ti0.48)O3 film was important in obtaining strong magnetoelectric coupling.
By using rare-earth-halide gas-phase-doping technique, we fabricated Yb-doped large-mode-area fiber preform. Yb concentration is of ∼9500ppmw in core area and 951W@1064nm laser output was obtained with a slope efficiency of 83.3%.
Thermal effects are critical limit relevant to the power scaling of single crystalline fiber laser. In this paper, thermal effects in thin-rod single crystalline fiber are numerically researched. The simulation results show that thermal effects can be effectively reduced by enhancing the convective coefficient and decreasing the diameter of single crystalline fiber. For the most thin-rod single crystalline fibers utilized with diameter of 1 mm and length of 40 mm, the maximum heat load is only about 107 W due to the thermal rupture effect, which limits the laser output power to ~1 kW levels. The numerical results provide references for the developments and designing of thin-rod SCF laser
Optical Second Harmonic Generation (SHG) is a nonlinear optical effect widely used for nonlinear optical microscopy and laser frequency conversion. The closed-form analytical solution of the nonlinear optical responses is essential for evaluating the optical responses of new materials whose optical properties are unknown a priori. Many approximations have therefore been employed in the existing analytical approaches, such as slowly varying approximation, weak reflection of the nonlinear polarization, transparent medium, high crystallographic symmetry, Kleinman symmetry, easy crystal orientation along a high-symmetry direction, phase matching conditions and negligible interference among nonlinear waves, which may lead to large errors in the reported material properties. To avoid these approximations, we have developed an open-source package named Second Harmonic Analysis of Anisotropic Rotational Polarimetry (♯SHAARP) for single interface (si) and in multilayers (ml) for homogeneous crystals. The reliability and accuracy are established by experimentally benchmarking with both the SHG polarimetry and Maker fringes predicted from the package using standard materials. SHAARP.si and SHAARP.ml are available through GitHub https://github.com/Rui-Zu/SHAARP and https://github.com/bzw133/SHAARP.ml, respectively.
CTFBGs with different center wavelengths are cascaded to broad the bandwidth to 20 nm (FWHM). The homemade duplexed CTFBG assists a 20.88 kW output of single fiber laser system with 18.6 dB of SRS suppression.
Ytterbium-doped silica fibers exhibit very broad absorption and emission bands, from 800nm to 1064nm for absorption and 970nm to 1200nm for emission. Therefore wide band lasers can be obtained using a wide variety of pump lasers. In this paper, the characteristics of high-doped Yb3+ fiber are analyzed and verified by experiment and a highly-doped Yb3+ fiber ring laser with short cavity has been presented. Comparing with normal Yb3+doped fiber, the relationship between the important characteristics of the Yb3+doped fiber laser such as threshold power, output power and laser parameters such as pump power, fiber length, output couple ratio is analyzed. Numerical results are coincident with the experiment phenomenon very well. A 1053 nm pulse has been achieved in our fiber laser. The output power is 6mW as pump power is 110mW and the slope efficiency is 17%. The Yb3+ fiber laser we produced can be used as a stable source in obtaining ultrafast pulse, fiber sense and optical communications.
On page 4811, Q. Wang, and co-workers describe ferro-electric ceramic nanowire arrays, which exhibit a high electrocaloric effect under low applied electric fields. The prepared lead-free ceramic nanostructured array is highly bendable and stretchable, and retains its excellent electrocaloric response in rigorous mechanical-deformation tests. These superior electrocaloric properties, in comparison to thin films, are validated using thermodynamic and phase-field simulations.
3D interconnected porous nitrogen-enriched graphene (NG) hydrogel was fabricated through ethanediamine as reducing and doping agent. The 3D porous structure of the NG enhances the accessibility to ion diffusion. Notably, when the NG material works as binder-free electrode, it achieves a high specific capacitance of 316.8 F g−1 at 0.5 A g−1. After the current density increased 40 folds, it still can reach 173.6 F g−1. 54.8% of capacitance retention can be achieved after the current density increased by 40 folds. This study provides a scalable approach to prepare 3D porous NG hydrosgel.
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