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Bi substituted YIG ceramics isolator for optical communication
摘要： We have succeeded in synthesizing transparent (BixY3-x)Fe5O12 [x ? 0e1.1] ceramics by reactive sintering method for the ?rst time in the world. The transmission spectrum of Bi-doped YIG showed character-istics comparable to the Bi:Gd3Fe5O12 single crystal produced by LPE method. The obtained Bi:YIG ceramic was uniformly composed of grains around below 5 mm. Residual pores, secondary phases and grain boundary phases were not detected. The distribution of Bi, Y, and Fe in this material was extremely uniform for up to x ? 0.4, but a rather high concentration of Bi at grain boundaries was detected by HR-TEM-EDS analysis for x ? 0.8. The Faraday rotation angle linearly increased with the Bi content, and the Faraday rotation angle per atomic % of Bi was (cid:2)31.2 deg./cm at 1550 nm, and this value was similar to the (Bi1.1Gd1.9)Fe5O12 single crystal produced by LPE method. In addition to LPE method which requires a seed substrate (Gd3Ga5O12) and a steep temperature gradient, it was demonstrated in this work that Bi-doped iron garnet can be synthesized by solid-state reactive sintering method, and also con?rmed that the magneto-optical performance of the polycrystalline Bi:YIG ceramics was equivalent to single crystal.
关键词： Isolator,YIG ceramics,Bi-substituted,Faraday rotation,Transparent
更新于2025-09-16 10:30:52
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Third-order nonlinear optical response of Yb:YAG ceramics under femtosecond laser irradiation
摘要： Transparent ceramic laser materials, as an important alternate of traditional laser gain medium materials, have aroused much attention for their excellent performance. Here, we investigated the third-order nonlinear susceptibility of high quality transparent Ytterbium-doped Yttrium Aluminium Garnet (Yb:YAG) ceramics. Under an ultrafast femtosecond laser irradiation, we experimentally demonstrated the nonlinear optical limiting and self-focusing behaviors of Yb:YAG ceramic by Z-scan method at 800 nm. It was found that Yb:YAG ceramics exhibit a relatively small nonlinear refractive index (~3.8 × 10?20 m2/W) which exerts little dependence on the Yb3+ doping concentration and laser intensity. This work could illustrate the application potential of transparent ceramic under high-power condition and can also provide useful design guidelines for high power ceramic laser system.
关键词： Third-order optical nonlinearity,Z-scan,Nonlinear refractive index,Yb:YAG ceramics
更新于2025-09-16 10:30:52
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Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs
摘要： There are several key requirements that a very good LED phosphor should meet, i.e., strong absorption, high quantum e?ciency, high colour purity, and high luminescence quenching temperature. The reported Rb2Bi(PO4)(MoO4):Eu3+ phosphors have all these properties. The Rb2Bi(PO4)(MoO4):Eu3+ phosphors emit bright red light if excited with near-UV radiation. The calculated colour coordinates show good stability in the 77–500 K temperature range. Moreover, sample doped with 50% Eu3+ possesses quantum e?ciency close to unity. Besides the powder samples, ceramic disks of Rb2Eu(PO4)(MoO4) specimen were also prepared, and the red light sources from these disks in combination with near-UV emitting LED were fabricated. The obtained results indicated that ceramic disks e?ciently absorb the emission of 375 and 400 nm LED and could be applied as a red component in phosphor-converted white LEDs.
关键词： thermal quenching,luminescent ceramics,red phosphor,colour coordinates,quantum e?ciency,luminous e?cacy
更新于2025-09-16 10:30:52
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Study on nonthermala??thermal processing boundary in drilling of ceramics using ultrashort pulse laser system with variable parameters over a wide range
摘要： Quality and throughput of laser material processing are influenced by multiple laser parameters as well as material properties. Since material degradation due to laser processing is generally related to heat-affected zone, quick optimization and realization of nonthermal process is one of the most important issues for higher-grade laser processing. In this work, we developed various parameter-controlled ultrashort pulse laser system that can control various laser parameters over a wide range, such as pulse duration over three orders of magnitude. Using this laser system (wavelength: 1033 nm, pulse duration: 0.4 to 400 ps, repetition: up to 1 MHz), we have investigated nonthermal–thermal processing boundary in drilling of ceramics: aluminum nitride (AlN) and yttria-stabilized zirconia (YSZ), with high and low thermal conductivity, respectively. As a result, the AlN ceramic exhibited strong dependence of ablation rate on fluence: low-, mid- and high-fluence regimes appeared with different logarithmic correlations. Further, the nonthermal–thermal process boundaries appeared, depending on the pulse duration. On the other hand, the ablation behavior of YSZ was much different from AlN; the ablation rate did not show distinct three regimes. Further, there were no nonthermal process windows for the YSZ. Therefore, the nonthermal–thermal process boundaries were governed by the laser parameters like pulse duration as well as the material thermal conductivity.
关键词： Ultrashort pulse laser,Ceramics,Drilling
更新于2025-09-16 10:30:52
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Fabrication and Laser Performances of Yb:Sc2O3 Transparent Ceramics from Different Combination of Vacuum Sintering and Hot Isostatic Pressing Conditions
摘要： In this paper we report on the preparation and laser performance of transparent 3at.% Yb:Sc2O3 ceramics by reactive sintering of commercially available powders under vacuum followed by hot isostatic pressing (HIP). Combinations of different vacuum sintering temperatures (1650 °C and 1750 °C) and different HIP treatments (1700 °C and 1800 °C at 200 MPa) were tested in order to understand how these steps influence the microstructure and thus the optical and lasing properties of the ceramic samples. All the samples showed a good optical quality. The microstructure analysis and the laser tests showed that the vacuum pre-sintering temperature is the key factor determining the quality of the samples and the laser performances. The best values of slope efficiency i.e. ηL=50% and output power i.e. Pout=6.62 W were obtained for the sample pre-sintered under vacuum at 1650 °C and hot isostatically pressed at 1800 °C.
关键词： Yb-doped Sesquioxides Laser Ceramics,Laser Ceramics,Hot Isostatic Pressing
更新于2025-09-12 10:27:22
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Impulse Laser Effect on Graphitized Surface of Y–TZP-Ceramics
摘要： The role of a graphite layer on the surface of ceramics based on tetragonal zirconia, partially stabilized by yttrium oxide (Y–TZP-ceramics) under the action of a pulsed laser was studied using original methodology. It has been found that surface graphitization increases the fraction of absorbed laser radiation, and as a result, heating, melting and evaporation of Y–TZP-ceramics occur under less intense modes, favorably affecting the use of pulsed laser radiation for surface modification.
关键词： Y–TZP-ceramics,graphite layer,pulsed laser effect,surface layer,roughness,surface morphology
更新于2025-09-12 10:27:22
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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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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Characterization of the Verdet Constant of Dy <sub/>2</sub> O <sub/>3</sub> Ceramics in the Two-Micron Spectral Range
摘要： High-power solid-state mid-IR lasers are being actively developed, as they possess the key properties for a vast number of technological applications [1] (e. g. lidar, gas sensing, or pump sources optical parametric oscillators) and are in a high demand for basic research as well [2]. These potentialities have recently led to intensive investigations of new mid-IR laser gain media [3,4] and other optical elements. One of the key components under investigation is an optical isolator (OI), a magneto-optical device enabling safe operation of a laser by preventing harmful back-reflections into the laser cavity. The development of high-power OIs is particularly challenging due to the severe thermal effects which arise because of the relatively high absorption of the currently available magneto-optical elements. Therefore, a lot of scientific effort is being put into the research of novel magneto-optical materials with the desired properties: high Verdet constant, low absorption and excellent thermal properties. All of these properties enable a reduction of the heat generated in the magneto-optical element. A large number of new magneto-optical materials for high-power OIs have been reported in the recent years. The vast majority of these reports targeted materials suitable for the wavelengths around 1 μm (corresponding to the neodymium and ytterbium doped gain media) in the task to find a better alternative to the most commonly used magneto-optical material for this spectral range – the terbium gallium garnet (TGG) [5]. In this manner, materials based on highly magnetically active rare-earth ions (e. g. Ce3+ [6], Tb3+ [7] or Ho3+ [8]) have been established as a possible next generation of magneto-optical materials for the visible and near-IR OIs. Some of these materials possess local transparency windows in the mid-IR as well, however, reports dealing with their magneto-optical characteristics in this region (or reports of any other suitable materials) were so far very rare. Nevertheless, Verdet constants of CeF3 crystal [9], DyxY0.95-xLa0.05O3 ceramics (with variable doping X = 0.7 – 0.9) [10] and EuF2 crystal [11] have been recently reported at the wavelength of ~1.94 μm, having ~7, ~10 - 14, and ~12 rad/Tm respectfully. We present broadband experimental characterizations of the Verdet constant of three novel material samples of Dy2O3-based ceramics in a broad spectral range 0.6 – 2.4 μm with the relative error of the measurement ~5%. An analytical approximation of the data is a challenging task due to the multiple resonances and absorption bands of Dy3+ ions within the measured range and is currently under investigation. The obtained values for the Verdet constant at 1.94 μm were 17.8, 22.2 and 26.8 rad/Tm predicting a high potential for Dy2O3 ceramics utilization in a high-power mid-IR OIs. The measured transmittances of our samples at 1.94 μm were equal to 54%, 72% and 76%.
关键词： mid-IR lasers,optical isolators,magneto-optical materials,Dy2O3 ceramics,Verdet constant
更新于2025-09-12 10:27:22
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Low-power laser-induced absorption in YSZ ceramics through formation of F-centers
摘要： Infrared lasers, especially those having a wavelength of either 10.6 μm or 1.06 μm are of great technological importance. Unfortunately, many dielectric materials, such as common ceramics absorb very poorly the latter wavelength since it falls within their large bandgap. However, some materials do not follow this general trend and strongly absorb moderate-energy-density (10–100 J/cm2) laser radiation of both types, although their bandgap extends into the infrared far beyond 1 μm and contains no intrinsic energy levels. The present study was motivated by the observation that IR-laser melting of some of these oddly behaving materials seems to be accompanied by appearance of strong visible absorption. The evolution of the optical properties and crystal structure of one of them, YSZ, as well as that of alumina, having a regular behavior, was studied by optical microscopy, SEM, XRD, Raman spectroscopy, optical spectroscopy and DRIFTS. As a result, it was shown for the first time that the melting of YSZ by 1.06 μm laser radiation is only possible due to F-centers forming in the tetragonal structure of the material, giving rise to a broad absorption continuum, which covers the entire bandgap of the material, including that wavelength, and when F-centers generation is inhibited, melting does not occur anymore. In order to explain that phenomenon, the possibility of multiple energy levels arising within the band gap because of F-center coupling and anisotropy was studied theoretically. Thus, a simple model was constructed, representing F-center clusters as coupled potential wells with variable separations between them and variable effective electron mass due to anisotropy. The model with just two wells produced multiple energy states distributed throughout the bandgap of the material, thus offering support for said hypothesis.
关键词： Absorption,Blackening,Zirconia,F-center,Ceramics,Laser
更新于2025-09-12 10:27:22
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Doping of Alumina Substrates for Laser Induced Selective Metallization
摘要： Laser induced selective activation and metallization of ceramics is a novel additive metal plating process enabling the application fine metallic paths or metallic surfaces on complex three-dimensionally shaped ceramic substrates. Metal deposition by electroless plating occurs selectively where the substrate has been locally activated by a preceding selective laser activation. The main influences on the process are the ceramic substrate material, its microstructural and optical properties as well as the laser type, laser process parameters and metallization parameters. Recent positive results with activation by a green picosecond laser were obtained only with oxygen vacancy containing alumina substrates sintered in hydrogen atmosphere. In order to be able to apply inexpensive conventional state-of-the-art sintering in air it was tried to modify the composition by doping with different oxides. 2 mass-% of fine particles of neodymium-, manganese-, samarium-, chromium-, nickel- iron-, ceria- and antimony doped tin-oxide were introduced into an alumina matrix by mixing and milling. Slip cast samples were sintered at 1500°C in air and machined. Laser activation was performed on polished sample surfaces using a Nd:YVO4 laser with a wavelength of 532 nm and a pulse length of 10 ps. Electroless plating was performed with commercially available copper electrolytes. Microstructural properties, laser-matter interaction and metallization effectivity were investigated. Doping of alumina substrates with antimony doped tin-oxide, chromium-, iron- and nickel-oxide results in very good metallization of laser activated areas. Dopants enable plating larger areas and writing fine circuit paths to integrate microelectronic devices. Other additives were ineffective. The activation mechanisms triggered by the dopants is not fully understood yet. Separation and identification of single mechanisms of the dopants is required. The influence of dopants and laser activation on the mechanical properties is to be studied.
关键词： laser activation,alumina,3D interconnect device,slip casting,Ceramics,electroless plating
更新于2025-09-12 10:27:22