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Nonradiative energy transfer of electronic excitation between Tm3+ ions in Y2O3:Tm laser ceramics
摘要： The cross relaxation of Tm3t ions (3H4→3F4, 3H6→3F4) in Y2O3:Tm laser ceramics was studied. This process significantly affects the creation of an inverse population between the 3F4 and 3H6 levels of Tm3t ions in two-micron lasers when they are pumped to the 3H4 level by laser diodes with a wavelength of λexc~800 nm. The efficiency of the cross-relaxation process of Tm3t ions (3H4→3F4, 3H6→3F4) was equal to 97% for Y2O3:Tm ceramics with the thulium concentration of 3 at.%. It was revealed that the nonradiative transfer of electron excitation energy by Tm3t ions through cross-relaxation (3H4→3F4, 3H6→3F4) is due to the dipole-dipole mechanism. The interaction microparameter CDA was determined equal to 9.2?10?39 cm6/s.
关键词： Y2O3,Optical properties,Laser ceramics,Spectroscopy
更新于2025-09-23 15:19:57
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Influences of the Sc3+ content on the microstructure and optical properties of 10?at.% Yb:Y3ScxAl5-xO12 laser ceramics
摘要： 10 at.% Yb:Y3ScxAl5-xO12 (x=0.25, 0.5, 1.0 and 1.5) transparent ceramics have been successfully fabricated by the solid state reaction method combined with vacuum sintering, whose transmittances reach 80% at 1100 nm with thickness of 3.0 mm. The full width at half maximum (FWHM) of the emission peaks located at about 1030 nm increases for increasing the Sc3+ content, and a maximum FWHM of 14.53 nm is obtained for 10 at.% Yb:Y3Sc1.5Al3.5O12 ceramics, which is 1.4 times larger than that of the 10 at.% Yb:Y3Al5O12 (Yb:YAG) ceramics. Finally, the laser performance of the 10 at.% Yb:Y3Sc1.5Al3.5O12 ceramics was tested and compared with that of a standard 10 at.% Yb:YAG sample. In quasi continuous wave (QCW) regime, a maximum laser output power of 10.8 W was obtained with the slope efficiency of 66.4%. The tuning range significantly broadens in the case of the Yb:YSAG sample, reaching a width of 86.2 nm.
关键词： Laser ceramics,Microstructure,Yb:Y3ScxAl5-xO12,Optical properties
更新于2025-09-19 17:13:59
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Optical Electronics (An Introduction) || 3. Bulk solid-state lasers
摘要： Solid-state lasers use solid-state laser medium as the working substance. Usually, solid work materials are incorporated in the matrix with a small amount of activated ions. Laser transition occurs between different energy levels during ion activation. Matrix materials are mainly crystal, glass, and ceramics, and activated ions can be categorized as trivalent rare earth metal ions, divalent rare earth metal ions, transition metal ions, and actinide metal ions.
关键词： crystal,activated ions,laser medium,heat capacity laser,ceramics,LD-pumped,glass,solid-state lasers
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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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