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Micro-channel fabrication on NiTi shape memory alloy substrate using Nd <sup>3+</sup> : YAG laser
摘要： Microchannel has been fabricated on NiTi shape memory alloy (SMA) sheet employing nanosecond Nd3+: YAG laser in open-air and underwater processing conditions. Microchannels were fabricated using three different laser wavelengths (1064, 532 and 355 nm) and scanning speeds (4, 10, 14 μm/s). A comparison of the effect of processing condition (open-air and underwater) and scanning speed on the kerf dimension has been examined. The scanning electron micrographs revealed no debris formation and no recast layer formation in underwater conditions whereas the surface irregularities were predominant in the open-air environment. Further, the influence of machining on NiTi in open-air and underwater was studied using UV-Vis spectroscopy. The austenitic phase attributed to shape memory characteristics was evident in processed material in comparison to unmachined material using the X-ray diffraction technique. In addition, differential scanning calorimetry demonstrated the phase transformation temperatures. The samples processed in open-air and underwater environment showed a significant shift in phase transformation temperatures. These laser-based processing techniques are highly useful in preserving smart material characteristics and fabrication of microchannels used in controlled volume drug delivery, microfluidic and waste or body heat-based actuated devices.
关键词： underwater,Nd3+: YAG,UV,NiTi,SMA,micro channeling,transformations,Laser
更新于2025-09-16 10:30:52
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Heat‐driven Tailored for Eliminating Nd <sup>3+</sup> Re‐clusters in Nd <sup>3+</sup> ,Gd <sup>3+</sup> ‐codoped SrF <sub/>2</sub> Laser Ceramic
摘要： Transparent Nd3+,Gd3+-codoped SrF2 laser ceramic was fabricated by a single-crystal ceramization (SCC) technique, and the fluorescence properties were also characterized. The results indicated that the SCC process would lead to reducing fluorescence properties of ceramic by re-clustering small amount of Nd3+ ions. In this paper, the re-clustering of Nd3+ ions were addressed by a simple thermal drive induced grains regrowth (TDIGR) treatment. The properties of the Nd3+,Gd3+-codoped SrF2 laser ceramic undergo the TDIGR were improved and close to precursor single crystal. Meanwhile, the transmittance of ceramic (Taverage@300-1400nm~92%) was hardly affected by the TDIGR treatment. Therefore, we have reason to believe that the combination of SCC and TDIGR is a suitable approach to obtain high optical quality neodymium, buffer ion-codoped alkaline-earth fluoride (Nd3+,B3+-codoped MF2) laser ceramics.
关键词： TDIGR,Nd3+,Gd3+-codoped SrF2,SCC,laser ceramics
更新于2025-09-12 10:27:22
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Nd <sup>3+</sup> :YAG laser based on the <sup>4</sup> F <sub/>3/2</sub> → <sup>4</sup> I <sub/>13/2</sub> secondary transition with a phase-conjugate electro-optically Q-switched open multiloop cavity
摘要： Lasing on the 4F3/2 → 4I13/2 secondary transition (λ = 1.34 μm) in a Nd3+ : YAG laser with phase conjugation by four-wave mixing directly in the active laser medium was experimentally studied in the regime of electro-optic Q-switching of an open multiloop cavity. The use of an electro-optic Q-switch with a controllable delay of its opening made it possible to increase the amplitude and temporal stabilities of the output laser parameters. The maximum laser pulse energy was 100 mJ at a pulse duration of 120 ns. The phase-conjugate radiation divergence was 0.8 mrad at beam quality Mx2 = My2 = 1.3. Nonlinear optical conversion of 1.34 μm laser radiation to visible radiation was achieved experimentally. Second and third harmonic generation at wavelengths of 0.67 and 0.446 μm with conversion efficiencies of 25 % and 8 %, respectively, was demonstrated.
关键词： phase conjugation,secondary transition,stability of laser parameters,Nd3+ : YAG laser,electro-optic Q-switching
更新于2025-09-12 10:27:22
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808nm‐light excited near‐infrared luminescent lanthanide metal‐organic frameworks for highly sensitive physiological temperature sensing
摘要： Ongoing demand for the accurate self-calibrated non-invasive thermometers for micro-/nano-scale applications, particular biomedical diagnosis, is driving the development of temperature sensors. Here we present a new type of lanthanide metal-organic framework having near-infrared absorption and near-infrared emission features. It is based on efficient Nd3+-to-Yb3+ energy transfer in 808 nm photo excitation. Our results show that the ratiometric parameter of Nd0.5Yb0.5TPTC can deliver good exponential type luminescence response to temperature in the physiological regime (293~328 K) with high relative sensitivity and accurate temperature resolution, as well as good biocompatibility and chemical stability. Such lanthanide-based materials are especially useful in the biomedical applications.
关键词： Temperature sensing,Near-infrared,luminescent,Nd3+/Yb3+-codoped,MOFs,Ratiometric
更新于2025-09-12 10:27:22
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Nd3+-doped mixed-anion fluoro-sulfo-phosphate glass for 1.06?μm solid-state laser
摘要： Fluoro-sulfo-phosphate poly-anionic glasses KPO3–AlF3–K2SO4 (KPFS) and Nd3+-doped samples (Nd–KPFS) were prepared by conventional melt-quenching method and their physical properties were comprehensively analyzed. Their actual glass compositions were carefully checked by di?erent methods. These glasses exhibit typically low linear refractive index nd (~ 1.482) and nonlinear refractive index n2 (~ 0.86 × 10?13 esu), high Abbe's number (~ 72.0) and moderate elasticity modulus E (~ 50.2 GPa). The spectroscopic properties of Nd–KPFS specimens are further evaluated by the Judd-Ofelt theory, and the results suggest that the stimulated radiative parameters can be enhanced by tuning sulfate contents. Besides, Nd–KPFS glasses present relatively long lifetime τexp (~ 428 μs) and large ?gure of merit FOM (~ 9.29 × 10?24 cm2 s). All of the results imply that such ?uoro-sulfo-phosphate glass would be a promising candidate for solid-state laser.
关键词： Physical properties,1.06 μm,Nd3+,Fluoro-sulfo-phosphate glass
更新于2025-09-11 14:15:04
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Thermal analysis and 1.38?μm CW laser performances based on a new tungstate crystal Nd3+:Na2La4(WO4)7
摘要： 1.38 μm diode-end-pumped crystalline lasers have important applications and studies are worthy to be conducted since it is not easy to realize the 1.38 μm laser emission in Nd3+-doped crystals. In this paper, a Nd3+:Na2La4(WO4)7 crystal with dimensions of f 21×37 mm3 was successfully grown by the Czochralski method. The distributions of heat on the end-pump facet and along the axial orientations were analyzed and its effect on the laser properties at 1.38 μm was considered. Then, based on the physical properties of the Nd3+:Na2La4(WO4)7 crystal and the results of the thermal effects analysis, we designed the oscillation cavity and finally a 1381 nm laser was demonstrated with the maximum output power of 1.87 W. The slope efficiency is 22.8%. Results show that the Nd3+:Na2La4(WO4)7 crystal will be advantageous for the applications of ~1.38 μm laser in many areas.
关键词： Nd3+:Na2La4(WO4)7,thermal analysis,Czochralski method,1.38 μm laser,diode-end-pumped
更新于2025-09-11 14:15:04
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Nd3+ doped new oxyfluoro tellurite glasses and glass ceramics containing NaYF4 nano crystals ??1.06?μm emission analysis
摘要： Oxyfluoro tellurite glasses with chemical composition TeO2-ZnO-YF3-NaF (TZYN), doped with Nd3+ in different concentrations were prepared by the melt-quenching technique. Judd–Ofelt analyses of Nd3+ ions in the precursor glasses were performed to evaluate the phenomenological intensity parameters Ω2,4,6. From the NIR emission spectra, characteristic parameters such as effective band with (?λeff) and stimulated emission cross section (σP) were calculated for the three observed transitions, 4F3/2 → 4I9/2, 4I11/2 and 4I13/2 and compared to other reported glasses. Based on the luminescence decay times of 4F3/2 excited state, the quantum efficiency was evaluated and it is highest for a 0.2 mol% Nd3+ doped glass (G-Nd2). Glass ceramics were obtained by controlled heat treatment of the glasses at 390oC for 5h (as determined by DSC), which is greater than the glass transition temperature Tg. Moreover, DSC results revealed that precipitation of the NdYF4 nanocrystalline phase (TC1) decreased with increasing Nd3+ concentration. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) investigations reveal that spherical NaYF4 nano-crystals are distributed homogeneously across the glassy matrix. The emission intensity of the 4F3/2→4I11/2 transition at 1.60 μm was enhanced in glass ceramics as compared to glasses because of the occupancy of the Nd3+ in NaYF4 nanocrystlline phase. The experimental lifetime value of 4F3/2 also enhanced from 124 to 187 μs from G-Nd2 glass to GC-Nd2 glass ceramic and decreased with increasing Nd3+ concentration.
关键词： Nd3+ doped,glass ceramics,1.06 μm emission analysis,NaYF4 nano crystals,oxyfluoro tellurite glasses
更新于2025-09-10 09:29:36
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Co-precipitation synthesis, structural characterization and fluorescent analysis of Nd3+ doped Y3Al5O12 and Yb3Al5O12 nanocrystallines
摘要： Nd3+, as one of the most important rare-earth (RE) ion, has been playing a significant role in pumping the infrared (IR) light. Depending on different synthesis strategies, doping content, and crystal lattice, however, Nd3+ always shows different IR intensity. In this work, we have fabricated two series of Nd3+ doped nanocrystallines that share with the same crystal structure, i.e., Nd3+ doped Y3Al5O12 (YAG) and Yb3Al5O12 (YbAG), through using the co-precipitation synthesis method while the ammonium bicarbonate as the precipitant agent. To reveal the influence of the synthesis conditions (e.g., synthetic temperature and pH value) on structural and florescent properties of Nd3+ doped YAG and YbAG nanocrystallines, several techniques have been performed in this work, including the X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric-differential scanning calorimeter (TG-DSC), Fourier transform infrared (FT-IR) spectroscopy, Raman and florescent spectroscopy spectra. Our results reveal that the optimal synthesis conditions are 1000?°C and pH 8 for YAG:Nd3+ and 900?°C and pH 9 for YbAG:Nd3+. Moreover, we also find the optimal Nd3+ doping contents of the YAG:Nd3+ and YbAG:Nd3+ nanocrystallines are 3% and 1.5%, which correspond to the strongest fluorescent intensity upon excitation at 808?nm and 980?nm, respectively. Typically, we reveal that substitution of Y with Yb ions could allow to enhancing the Nd3+ fluorescent intensity upon excitation at 808?nm. This work provides new insights into designing excellent crystal materials that can allow us to realize the laser transparent ceramics.
关键词： Nd3+ doped YbAG,fluorescent analysis,Nd3+ doped YAG,co-precipitation synthesis,structural characterization
更新于2025-09-09 09:28:46
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The effects of 150?kGy dose γ rays on Nd3+ doped lead fluoroborate glasses
摘要： Authors aim to make a study on gamma (γ) rays effects over inorganic glassy materials. The Nd3+ content as well as high energetic induced radiation in the glass compositions resulted in the B-O-B bonds depolymerization creating NBOs (Non-Bridging Oxygens) in the matrices, interpreted through FTIR (Fourier Transform Infrared) spectra. The decrease in the Tg, Hr and H values obtained from Differential Scanning Calorimetry (DSC) thermograms and Vickers Microhardness Tester respectively, proved the changes in the glass structure after irradiation. The drastic decrease in the intensities of UV-VIS absorption and Photoluminescence (PL) emission peaks after irradiation, prompted the creation of defect points in the samples. The JO (Judd-Ofelt) theory was implemented to understand the asymmetric and covalent nature of the matrix and also to predict the radiative properties. The EPR (Electron Paramagnetic Resonance) spectra proved the presence of defects in the samples both pre and post irradiation. These changes were correlated with the Nd (Neodymium) and O (Oxygen) concentration ratios, studied through EDS (Energy-Dispersive X-ray spectroscopy), which showed decrease in the elemental composition post irradiation. The UV-VIS differential absorption spectra of the samples after γ irradiation depicts defects in the glass network with feasibility in valency change from Nd3+ to Nd2+ and decrease in Nd3+ ions number density after irradiation. Dipole-Dipole interactions within the ions were analyzed through lifetime decay measurement. 1.0 mol% of Nd3+ ions showed better radiation resistant nature and quality optical properties when compared to other samples both before and after γ rays interactions.
关键词： Gamma rays,EPR,Nd3+,PL,JO
更新于2025-09-04 15:30:14