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Junjie Zhang - One of the best experts on this subject based on the ideXlab platform.
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thermal and luminescent properties of 2 μm emission in thulium sensitized holmium doped silicate Germanate glass
Photonics Research, 2016Co-Authors: Rong Chen, Junjie Zhang, Ying Tian, Xufeng Jing, Hellmut Eckert, Xianghua ZhangAbstract:In this paper, we present the luminescent properties of Tm3+/Ho3+ co-doped new glass. A series of silicate-Germanate glass was prepared by the conventional melt-quenching method. In the Tm3+/Ho3+ co-doped silicate-Germanate glass, a strong emission of 2 μm originating from the Ho3+:I75→I85 transition can be observed under conventional 808 nm pumping. The characteristic temperatures, structure, and absorption spectra have been measured. The radiative properties of Ho3+ in the prepared glass were calculated. The emission cross section of Ho3+ ions transition can reach 4.78×10−21 cm2 around 2 μm, and the FWHM is as high as 153 nm. The energy transfer efficiency between Ho3+ and Tm3+ has a large value (52%), which indicates the Tm3+/Ho3+ co-doped silicate-Germanate glass is a suitable candidate for the 2 μm laser. Moreover, the energy transfer mechanism between Tm3+ and Ho3+ ions was investigated.
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mid infrared fluorescence energy transfer process and rate equation analysis in er3 doped Germanate glass
Scientific Reports, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Fangze Chen, Muzhi Cai, Xufeng Jing, Fengchao Wang, Qinyuan ZhangAbstract:Mid-infrared fluorescence, energy transfer process and rate equation analysis in Er 3+ doped Germanate glass
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the effect of la2o3 in tm3 doped Germanate tellurite glasses for 2 μm emission
Scientific Reports, 2015Co-Authors: Yapei Peng, Junjie Zhang, Xinqiang Yuan, Long ZhangAbstract:A Germanate-tellurite glass (GeO2-TeO₂-K₂O-Nb₂O₅-La₂O₃) with thulium doping has been investigated for application as a laser material around 2.0 μm regions. Under the 808 nm laser diode pumped, intense 1.8 μm emission is obtained. Based on the absorption spectra, radiative properties are predicted using Judd-Ofelt theory. The maximum value of emission cross-section of Tm(3+) around 1.8 μm can reach 1.46 × 10(-20) cm(2), which indicated that the Germanate-tellurite glass may provide high gain as a good medium for efficient 1.8 μm laser system.
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analysis of energy transfer process based emission spectra of erbium doped Germanate glasses for mid infrared laser materials
Journal of Alloys and Compounds, 2015Co-Authors: Muzhi Cai, Tao Wei, Ying Tian, Beier Zhou, Jiajia Zhou, Junjie ZhangAbstract:Abstract Er 3+ activated Germanate glass with good thermal stability was prepared. Bonding parameters have been calculated and the nature of ionic bonding of the Germanate glass has been determined. Mid-infrared fluorescence was observed and corresponding radiative properties were investigated. For Er 3+ : 4 I 11/2 → 4 I 13/2 transition, high spontaneous radiative transition probability (30.09 s −1 ), large emission cross section ((14.84 ± 0.10) × 10 −21 cm 2 ) and superior gain performance were obtained from the prepared glass. Besides, energy transfer processes concerning the 2.7 μm emission were also discussed in detail. According to simplified rate equation and Dexter’s theory, energy transfer microscopic parameters were computed to elucidate observed 2.7 μm emissions. Results demonstrate that the prepared Germanate glass possessing excellent spectroscopic properties might be an attractive candidate for mid-infrared laser or amplifier.
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comprehensive evaluation of the structural absorption energy transfer luminescent properties and near infrared applications of the neodymium doped Germanate glass
Journal of Alloys and Compounds, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Muzhi Cai, Xufeng Jing, Cong Tian, Long ZhangAbstract:Abstract Nd 3+ doped Germanate glass with good thermal stability was investigated through absorption, near-infrared emission spectrum and lifetime measurement. Intensity parameters ( Ω 2,4,6 ) and spectroscopic quality factor ( χ = Ω 4 / Ω 6 ) were analyzed in detail on the basis of the Judd–Ofelt theory. The calculations of bonding parameters and the degree of ionic or covalent bonding character demonstrate the nature of ionic bonding of the prepared sample. It is found that the present glass possesses large spectroscopic quality factor of 93%, high stimulated emission cross section, fluorescence branching ratio and optical gain parameters as well as lower saturation intensity at 1.05 μm. Thus, the excellent radiative properties owing to 4 F 3/2 → 4 I 11/2 transition reveal the favorable laser action at 1.05 μm. Nd 3+ doped Germanate glass might have potential advantages for near-infrared applications.
Ying Tian - One of the best experts on this subject based on the ideXlab platform.
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thermal and luminescent properties of 2 μm emission in thulium sensitized holmium doped silicate Germanate glass
Photonics Research, 2016Co-Authors: Rong Chen, Junjie Zhang, Ying Tian, Xufeng Jing, Hellmut Eckert, Xianghua ZhangAbstract:In this paper, we present the luminescent properties of Tm3+/Ho3+ co-doped new glass. A series of silicate-Germanate glass was prepared by the conventional melt-quenching method. In the Tm3+/Ho3+ co-doped silicate-Germanate glass, a strong emission of 2 μm originating from the Ho3+:I75→I85 transition can be observed under conventional 808 nm pumping. The characteristic temperatures, structure, and absorption spectra have been measured. The radiative properties of Ho3+ in the prepared glass were calculated. The emission cross section of Ho3+ ions transition can reach 4.78×10−21 cm2 around 2 μm, and the FWHM is as high as 153 nm. The energy transfer efficiency between Ho3+ and Tm3+ has a large value (52%), which indicates the Tm3+/Ho3+ co-doped silicate-Germanate glass is a suitable candidate for the 2 μm laser. Moreover, the energy transfer mechanism between Tm3+ and Ho3+ ions was investigated.
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mid infrared fluorescence energy transfer process and rate equation analysis in er3 doped Germanate glass
Scientific Reports, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Fangze Chen, Muzhi Cai, Xufeng Jing, Fengchao Wang, Qinyuan ZhangAbstract:Mid-infrared fluorescence, energy transfer process and rate equation analysis in Er 3+ doped Germanate glass
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analysis of energy transfer process based emission spectra of erbium doped Germanate glasses for mid infrared laser materials
Journal of Alloys and Compounds, 2015Co-Authors: Muzhi Cai, Tao Wei, Ying Tian, Beier Zhou, Jiajia Zhou, Junjie ZhangAbstract:Abstract Er 3+ activated Germanate glass with good thermal stability was prepared. Bonding parameters have been calculated and the nature of ionic bonding of the Germanate glass has been determined. Mid-infrared fluorescence was observed and corresponding radiative properties were investigated. For Er 3+ : 4 I 11/2 → 4 I 13/2 transition, high spontaneous radiative transition probability (30.09 s −1 ), large emission cross section ((14.84 ± 0.10) × 10 −21 cm 2 ) and superior gain performance were obtained from the prepared glass. Besides, energy transfer processes concerning the 2.7 μm emission were also discussed in detail. According to simplified rate equation and Dexter’s theory, energy transfer microscopic parameters were computed to elucidate observed 2.7 μm emissions. Results demonstrate that the prepared Germanate glass possessing excellent spectroscopic properties might be an attractive candidate for mid-infrared laser or amplifier.
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comprehensive evaluation of the structural absorption energy transfer luminescent properties and near infrared applications of the neodymium doped Germanate glass
Journal of Alloys and Compounds, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Muzhi Cai, Xufeng Jing, Cong Tian, Long ZhangAbstract:Abstract Nd 3+ doped Germanate glass with good thermal stability was investigated through absorption, near-infrared emission spectrum and lifetime measurement. Intensity parameters ( Ω 2,4,6 ) and spectroscopic quality factor ( χ = Ω 4 / Ω 6 ) were analyzed in detail on the basis of the Judd–Ofelt theory. The calculations of bonding parameters and the degree of ionic or covalent bonding character demonstrate the nature of ionic bonding of the prepared sample. It is found that the present glass possesses large spectroscopic quality factor of 93%, high stimulated emission cross section, fluorescence branching ratio and optical gain parameters as well as lower saturation intensity at 1.05 μm. Thus, the excellent radiative properties owing to 4 F 3/2 → 4 I 11/2 transition reveal the favorable laser action at 1.05 μm. Nd 3+ doped Germanate glass might have potential advantages for near-infrared applications.
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structural origin and energy transfer processes of 1 8 μm emission in tm3 doped Germanate glasses
Journal of Physical Chemistry A, 2011Co-Authors: Ying Tian, Junjie ZhangAbstract:A detailed characterization of structural analysis and energy transfer (ET) process in Tm3+ doped Germanate glasses has been presented. The thermal stability and Raman spectroscopic analysis of the host glass structure has been discussed. It is observed that replacing GeO2 by Ga2O3 resulted in decreasing of glass transition temperature and largest phonon energy. Increasing concentration of Ga2O3 decreases the density of cross-linking of the Germanate glass network, and weaker Ga–O bonds result in lower phonon energy. The influences of the concentrations of Ga2O3 and the glass structure on the ET have also been analyzed. The extended overlap integral method is used to calculate the microparameters of the energy transfer and the critical distance. The results show that the transference Tm → Tm (3H4, 3H6 → 3H6, 3H4) energy migration is not phonon dependent in the quasiresonant processes, while the cross relaxation Tm → Tm (3H4, 3H6 → 3F4, 3F4) is a multiphonon mechanism dominated by one-phonon creation (∼96%...
Kwang Hwa Lii - One of the best experts on this subject based on the ideXlab platform.
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flux synthesis crystal structure and photoluminescence of a heterometallic uranyl europium Germanate with u o eu linkage k4 uo2 eu2 ge2o7 2
Inorganic Chemistry, 2013Co-Authors: Shihpu Liu, Kwang Hwa Lii, Mengling Chen, Bor Chen ChangAbstract:Crystals of a uranyl-europium Germanate, K4[(UO2)Eu2(Ge2O7)2], have been grown at high temperature from a KF-MoO3 flux and structurally characterized by single-crystal X-ray diffraction. The structure contains PaCl5-type chains formed of edge-sharing EuO7 pentagonal bipyramids that are connected by diGermanate groups such that layers of europium Germanate are formed. Neighboring layers are further linked by UO6 tetragonal bipyramids through uranyl ion oxygen atoms to generate a 3D framework with 6-ring channels where the K+ cations are located. The structure contains an unusual heterometallic U═O–Eu linkage. Photoluminescence studies show strong red emission at room temperature. The relative intensities of the 5D0 → 7F1 and 5D0 → 7F2 transitions confirm that the europium site lacks an inversion center. All of the emission lines show similar decay curves, which can be well-fitted by a single exponential decay function with radiative lifetimes of 0.53 ± 0.03 ms. No emission is observed in the region from 45...
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mixed valence uranium Germanate and silicate cs x u v o u iv v o 2 ge2o7 2 x 3 18 and cs4 u v o u iv v o 2 si2o7 2
Inorganic Chemistry, 2012Co-Authors: Chunliang Chen, Quang Bac Nguyen, Kwang Hwa Lii, Chih Shan ChenAbstract:A new mixed-valence uranium Germanate and the silicate analogue have been synthesized under hydrothermal conditions at 600 °C and 165 MPa. Their crystal structures contain infinite −UV–O–UIV/V–O–UIV/V–O–UV– chains that are connected by Ge2O7 or Si2O7 groups to form a 3D framework with six-ring channels where the Cs+ cations are located. Two of the Cs sites in the Germanate are partially occupied. Bond-valence-sum calculation and an U 4f X-ray photoelectron spectroscopy study confirm the valence states of the uranium.
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cs3uge7o18 a pentavalent uranium Germanate containing four and six coordinate germanium
Inorganic Chemistry, 2012Co-Authors: Quang Bac Nguyen, Chunliang Chen, Yunwei Chiang, Kwang Hwa LiiAbstract:A pentavalent uranium Germanate, Cs3UGe7O18, was synthesized under high-temperature, high-pressure hydrothermal conditions at 585 °C and 160 MPa and structurally characterized by single-crystal X-ray diffraction and infrared spectroscopy. The valence state of uranium was confirmed by X-ray photoelectron spectroscopy and electron paramagnetic resonance. The room-temperature EPR spectrum can be simulated with two components using an axial model that are consistent with two distinct sites of uranium(V). In the structure of the title compound, each [6]GeO6 octahedron is bonded to six three-membered single-ring [4]Ge3O96– units to form Germanate triple layers in the ab plane. Each layer contains nine-ring windows; however, these windows are blocked by adjacent layers. The triple layers are further connected by UO6 octahedra to form a three-dimensional framework with intersecting six-ring channels along the ⟨110⟩ directions. The Cs+ cation sites are fully occupied, ordered, and located in the cavities of the f...
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cs4uge8o20 a tetravalent uranium Germanate containing four and five coordinate germanium
Inorganic Chemistry, 2011Co-Authors: Quang Bac Nguyen, Kwang Hwa LiiAbstract:A very rare tetravalent uranium Germanate has been synthesized under hydrothermal conditions at 585 °C and 160 MPa. Its structure contains layers of single-ring Ge3O96– Germanate anions that are connected by UO6 octahedra and dimers of edge-sharing GeO5 trigonal bipyramids to form a three-dimensional framework with intersecting 6- and 7-ring channels. UV–visible, photoluminescence, and U 4f X-ray photoelectron spectroscopy were used to confirm the valence state of uranium.
Tao Wei - One of the best experts on this subject based on the ideXlab platform.
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mid infrared fluorescence energy transfer process and rate equation analysis in er3 doped Germanate glass
Scientific Reports, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Fangze Chen, Muzhi Cai, Xufeng Jing, Fengchao Wang, Qinyuan ZhangAbstract:Mid-infrared fluorescence, energy transfer process and rate equation analysis in Er 3+ doped Germanate glass
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analysis of energy transfer process based emission spectra of erbium doped Germanate glasses for mid infrared laser materials
Journal of Alloys and Compounds, 2015Co-Authors: Muzhi Cai, Tao Wei, Ying Tian, Beier Zhou, Jiajia Zhou, Junjie ZhangAbstract:Abstract Er 3+ activated Germanate glass with good thermal stability was prepared. Bonding parameters have been calculated and the nature of ionic bonding of the Germanate glass has been determined. Mid-infrared fluorescence was observed and corresponding radiative properties were investigated. For Er 3+ : 4 I 11/2 → 4 I 13/2 transition, high spontaneous radiative transition probability (30.09 s −1 ), large emission cross section ((14.84 ± 0.10) × 10 −21 cm 2 ) and superior gain performance were obtained from the prepared glass. Besides, energy transfer processes concerning the 2.7 μm emission were also discussed in detail. According to simplified rate equation and Dexter’s theory, energy transfer microscopic parameters were computed to elucidate observed 2.7 μm emissions. Results demonstrate that the prepared Germanate glass possessing excellent spectroscopic properties might be an attractive candidate for mid-infrared laser or amplifier.
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comprehensive evaluation of the structural absorption energy transfer luminescent properties and near infrared applications of the neodymium doped Germanate glass
Journal of Alloys and Compounds, 2015Co-Authors: Tao Wei, Junjie Zhang, Ying Tian, Muzhi Cai, Xufeng Jing, Cong Tian, Long ZhangAbstract:Abstract Nd 3+ doped Germanate glass with good thermal stability was investigated through absorption, near-infrared emission spectrum and lifetime measurement. Intensity parameters ( Ω 2,4,6 ) and spectroscopic quality factor ( χ = Ω 4 / Ω 6 ) were analyzed in detail on the basis of the Judd–Ofelt theory. The calculations of bonding parameters and the degree of ionic or covalent bonding character demonstrate the nature of ionic bonding of the prepared sample. It is found that the present glass possesses large spectroscopic quality factor of 93%, high stimulated emission cross section, fluorescence branching ratio and optical gain parameters as well as lower saturation intensity at 1.05 μm. Thus, the excellent radiative properties owing to 4 F 3/2 → 4 I 11/2 transition reveal the favorable laser action at 1.05 μm. Nd 3+ doped Germanate glass might have potential advantages for near-infrared applications.
Meisong Liao - One of the best experts on this subject based on the ideXlab platform.
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sim 2 mu text m single mode laser output in tm 3 doped tellurium Germanate double cladding fiber
IEEE Photonics Technology Letters, 2015Co-Authors: Peiwen Kuan, Danping Chen, Meisong Liao, Lili HuAbstract:A single-mode laser output of 0.75 W near $2~\mu \text{m}$ was obtained with a slope efficiency of 28.7% with respect to the absorbed pump power when a self-developed double-cladding Tm3+-doped tellurium Germanate glass fiber laser was pumped using a 793-nm diode laser. The core glass possesses an infrared cutoff edge reaching $\sim 5~\mu \text{m}$ . The calculated peak emission cross section of Tm3+ at $1.9~\mu \text{m}$ was $6.8 \times 10^{-21}$ cm $^{2}$ . The measured fluorescence lifetime of 3F4 energy level was 2.96 ms. A single-mode double-cladding tellurium Germanate glass fiber was fabricated in house using the rod-in-tube drawing technique. The lasing threshold was 0.56 W and the lasing wavelength was centered at 1968 nm. Spatial beam quality of the fiber was measured and a value of $M^{2} =1.36$ was obtained.
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tm3 doped tellurium Germanate glass and its double cladding fiber for 2 μm laser
Materials Letters, 2015Co-Authors: Song Gao, Peiwen Kuan, Longfei Wang, Meisong LiaoAbstract:Abstract The thermal and spectroscopic performance of 40GeO2–35TeO2–15PbO–5Al2O3–5(CaO+SrO)–1Tm2O3 (in mol%) tellurium Germanate glass suitable for fiber drawing is investigated. The glass developed has a low phonon energy of ~780 cm−1 and excellent thermal stability against devitrification. The peak emission cross-section of Tm3+ at 1.8 μm is calculated to be 5.18×10–21 cm2 and the measured lifetime is 0.83 ms. Tm3+-doped tellurium Germanate double-cladding fiber with a hexagonal-shaped inner cladding is fabricated by a stacking-and-drawing method, and a laser output of 1.938 μm is realized in a 250-mm-long fiber.