We demonstrate the spectroscopic and laser performance before and after 100 Mrad gamma-ray irradiation on an Er,Pr:GYSGG crystal grown by the Czochralski method. The additional absorption of Er,Pr:GYSGG crystal is clo...We demonstrate the spectroscopic and laser performance before and after 100 Mrad gamma-ray irradiation on an Er,Pr:GYSGG crystal grown by the Czochralski method. The additional absorption of Er,Pr:GYSGG crystal is close to zero in the 968 nm pumping and 2.7-3 μm laser wavelength regions. The lifetimes of the upper and lower levels show faint decreases after gamma-ray irradiation. The maximum output powers of 542 and 526 mW with the slope efficiencies of 17.7% and 17.0% are obtained, respectively, on the GYSGG/Er,Pr:GYSGG composite crystal before and after the gammaray irradiation. These results suggest that Er,Pr:GYSGG crystal as a laser gain medium possesses a distinguished antiradiation ability for application in space and radiant environments.展开更多
Crystallization kinetics of Pr8Fe86-xZrxB6 (x=0, 1, 2) amorphous alloys was studied by DTA and XRD methods. The experimental results showed that the crystalline phases of Pr8Fe86B6 alloy are composed of α-Fe phase, P...Crystallization kinetics of Pr8Fe86-xZrxB6 (x=0, 1, 2) amorphous alloys was studied by DTA and XRD methods. The experimental results showed that the crystalline phases of Pr8Fe86B6 alloy are composed of α-Fe phase, Pr2Fe23B3 and Pr2Fe14B, when crystallization temperature is below 900 ℃. The activation energy of α-Fe phase remains relatively constant about 306.09 kJ/mol, as the crystalline fraction of α-Fe phase is below 8 %. At the beginning of crystallization, the activation energy of Pr2Fe23B3 and Pr2Fe14B phases are 510.85 kJ/mol and 725.97 kJ/mol, respectively, and then the activation energy of three phases declines with increasing the crystalline fraction. The crystallization behavior of α-Fe and Pr2Fe14B essentially results in the formation of a α-Fe/Pr2Fe14B composite microstructure with a coarse grain size in annealed Pr8Fe86B6 alloy, which is attributed to a difficult nucleation and an easy growth for both the α-Fe and Pr2Fe14B in the alloy. Zr can be used to change the crystallization behavior of the α-Fe phase in Pr-Fe-B amorphous alloy, which is helpful to the formation of the α-Fe/Pr2Fe14B nanocomposite microstructure with a fine grain size for the α-Fe phase in the alloy.展开更多
Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radia...Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J',oscillator strengths PJ,J',radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spectra.The 1G4 absorption band was not observed.A very strong emission band at 601 nm(1D2→3H4) was observed in the emission spectra.The experimental lifetime for this level was compared with that obtained theoretically by using J-O approach.展开更多
Amorphous (Nd,Pr)13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isother...Amorphous (Nd,Pr)13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.展开更多
The effects of Zr on crystallization kinetics of Pr Fe B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr 8Fe 86- x Zr x B 6 ( x =0, 1, 2) amorphous alloys, the final crystalliz...The effects of Zr on crystallization kinetics of Pr Fe B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr 8Fe 86- x Zr x B 6 ( x =0, 1, 2) amorphous alloys, the final crystallized mixture is α Fe and Pr 2Fe 14 B, and the metastable Pr 2Fe 23 B 3 phase occurs during crystallization of Pr 8Fe 86 B 6 amorphous alloy, not during crystallization of Pr 8Fe 86- x Zr x B 6( x =1, 2) amorphous alloys. By analyzing the activation energy of crystallization, the formation of an α Fe/Pr 2Fe 14 B composite microstructure with a coarse grain size in annealed Pr 8Fe 86 B 6 alloy, is attributed to a difficult nucleation and an easy growth for both the α Fe and Pr 2Fe 14 B in the alloy. The addition of Zr can be used to change the crystallization behavior of the α Fe phase in Pr Fe B amorphous alloy, which is helpful to reduce the grain size for the α Fe phase.展开更多
Bulk amorphous crystal and microcrystal for Pr60Cu(20-x)Ni10Al10Fex (x=0, 8, 15, 20) with the diameter of Φ 2～6 mm were manufactured by electric arc smelting, high frequency heating and copper mold upper suction cas...Bulk amorphous crystal and microcrystal for Pr60Cu(20-x)Ni10Al10Fex (x=0, 8, 15, 20) with the diameter of Φ 2～6 mm were manufactured by electric arc smelting, high frequency heating and copper mold upper suction casting, and its structure was analyzed by X-ray diffract meter. It showed soft magnetic characteristic gradually when Fe content in it was up to 8%. The material was applied to magnetic-electric sensor as key component, output signal of which was measured with the change of Fe content. It shows that the signal changes from weak to strong with the increase of Fe content and presents the largest peak value when Fe is replaced by Cu completely.展开更多
A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes(LDs) is conducted for the thermal lensing compensation. The analyses of the thermal dist...A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes(LDs) is conducted for the thermal lensing compensation. The analyses of the thermal distribution and thermal focal length show that the bonding rod possesses a high cooling efficiency and weak thermal lensing effect compared with the conventional Er,Pr:GYSGG rod. Moreover, the laser characteristics of maximum output power, slope efficiency, and laser beam quality of the bonding rod with concave end-faces operated at 2.79 μm are improved under the high-repetition-rate operation. A maximum output power of 13.96 W is achieved at 150-Hz and 200-μs pulse width,corresponding to a slope efficiency of 17.7% and an electrical-to-optical efficiency of 12.9%. All results suggest that the combination of thermal bonding and concave end-face is a suitable structure for thermal lensing compensation.展开更多
Fluorescence decay curves of the 3P0 and 1D2 manifolds in Pr 3+ doped PbWO4 crystal were measured at room temperature and fluorescence lifetimes of both manifolds were estimated. Combining with the radiative lifetimes...Fluorescence decay curves of the 3P0 and 1D2 manifolds in Pr 3+ doped PbWO4 crystal were measured at room temperature and fluorescence lifetimes of both manifolds were estimated. Combining with the radiative lifetimes of the manifolds calculated on the basis of the modified J-O theory, the main mechanisms for the fluorescence quenching of the manifolds were analyzed. The multi-phonon relaxation and the cross-relaxation energy transfer are the major reasons for the fluorescence quenching of the 3P0 and 1D2 manifolds, respectively. The Inokuti-Hirayama model was used to analyze the fluorescence decay curve of the 1D2 manifold and the cross-relaxation of dipole-dipole interaction was confirmed. Consequently, the 3P0 manifold is more favorable as an upper laser level than the 1D2 manifold.展开更多
The single crystal of GdP 5O 14 :Sm 3+ ,Pr 3+ (GdPP:Sm,Pr) was grown by the hydrothermal method. The crystal belongs to the monoclinic space group P2 1/ C by X ray powder diffraction results. The dependence of Pr 3+ i...The single crystal of GdP 5O 14 :Sm 3+ ,Pr 3+ (GdPP:Sm,Pr) was grown by the hydrothermal method. The crystal belongs to the monoclinic space group P2 1/ C by X ray powder diffraction results. The dependence of Pr 3+ ion concentration in GdPP:Sm,Pr crystals on the emission intensity of 4 G 5/2 → 6 H 7/2 transitions of Sm 3+ ion and the energy transfer between Sm 3+ and Pr 3+ ions have been investigated and discussed.展开更多
The 3μm laser emission of Er 3+ ( 4 I 11/2 → 4 I 13/2 )in the YAG crystal is,in principle,selfsaturation transition,the lifetime of the upper laser level( 4 I 11/2 )being smaller than that of the olwer one( 4 I 13/2...The 3μm laser emission of Er 3+ ( 4 I 11/2 → 4 I 13/2 )in the YAG crystal is,in principle,selfsaturation transition,the lifetime of the upper laser level( 4 I 11/2 )being smaller than that of the olwer one( 4 I 13/2 ).The effect of the selfsaturation limit the laser output. In present work,for the first time,we report on the investigation of the utility of Pr 3+ as a sensitizer of Er 3+ ion,using Pr 3+ 4 f 2-4 f5d transition.The radiation emission from 4f5d configuration of Pr 3+ ion have been observed in the YAG∶Pr 3+ crystal.This shows that under suitable conditions this radiant process can compete successfully by non radiative decay to the 4 f configuration.Using Er 3+ Pr 3 codoped YAG it is possible to predict the position of the lowest 4 f 2-4 f5d absorption bands of Pr 3+ ion in the ultraviolet range and to present the occurrence of the energy transfer from Pr 3+ to Er 3+ ion.By xenon flash lamp pumped 2.93μm laser action in the YAG∶(Er 3+ ,Pr 3+ ) crystals was demonstrated at room temperature.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB1102301)the National Natural Science Foundation of China(Grant Nos.51272254,61405206,and 51502292)the Open Research Fund of the State Key Laboratory of Pulsed Power Laser Technology,Electronic Engineering Institute,China(Grant No.SKL2015KF01)
文摘We demonstrate the spectroscopic and laser performance before and after 100 Mrad gamma-ray irradiation on an Er,Pr:GYSGG crystal grown by the Czochralski method. The additional absorption of Er,Pr:GYSGG crystal is close to zero in the 968 nm pumping and 2.7-3 μm laser wavelength regions. The lifetimes of the upper and lower levels show faint decreases after gamma-ray irradiation. The maximum output powers of 542 and 526 mW with the slope efficiencies of 17.7% and 17.0% are obtained, respectively, on the GYSGG/Er,Pr:GYSGG composite crystal before and after the gammaray irradiation. These results suggest that Er,Pr:GYSGG crystal as a laser gain medium possesses a distinguished antiradiation ability for application in space and radiant environments.
基金Item Sponsored by National Natural Science Foundation of China(19974035)Natural Science Foundation of Hebei Province(599240)
文摘Crystallization kinetics of Pr8Fe86-xZrxB6 (x=0, 1, 2) amorphous alloys was studied by DTA and XRD methods. The experimental results showed that the crystalline phases of Pr8Fe86B6 alloy are composed of α-Fe phase, Pr2Fe23B3 and Pr2Fe14B, when crystallization temperature is below 900 ℃. The activation energy of α-Fe phase remains relatively constant about 306.09 kJ/mol, as the crystalline fraction of α-Fe phase is below 8 %. At the beginning of crystallization, the activation energy of Pr2Fe23B3 and Pr2Fe14B phases are 510.85 kJ/mol and 725.97 kJ/mol, respectively, and then the activation energy of three phases declines with increasing the crystalline fraction. The crystallization behavior of α-Fe and Pr2Fe14B essentially results in the formation of a α-Fe/Pr2Fe14B composite microstructure with a coarse grain size in annealed Pr8Fe86B6 alloy, which is attributed to a difficult nucleation and an easy growth for both the α-Fe and Pr2Fe14B in the alloy. Zr can be used to change the crystallization behavior of the α-Fe phase in Pr-Fe-B amorphous alloy, which is helpful to the formation of the α-Fe/Pr2Fe14B nanocomposite microstructure with a fine grain size for the α-Fe phase in the alloy.
基金supported by the National Natural Science Foundation of China (50590402 and 50802100)
文摘Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J',oscillator strengths PJ,J',radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spectra.The 1G4 absorption band was not observed.A very strong emission band at 601 nm(1D2→3H4) was observed in the emission spectra.The experimental lifetime for this level was compared with that obtained theoretically by using J-O approach.
基金supported by the National Natural Science Foundation of China (No. 50744014)the National Basic Research Foundation (No. 2004CCA04000)+3 种基金Science and Technology Department of Zhejiang Province (Nos. 2008C21046 and 2008C11086-1)the Natural Science Foundation of Zhejiang Province,China (No. Y406389)the Research and Development Program of Ningbo Bureau of Science and Technology (No. 2006B100054)K.C.Wong Magna Found in Ningbo University
文摘Amorphous (Nd,Pr)13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.
文摘The effects of Zr on crystallization kinetics of Pr Fe B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr 8Fe 86- x Zr x B 6 ( x =0, 1, 2) amorphous alloys, the final crystallized mixture is α Fe and Pr 2Fe 14 B, and the metastable Pr 2Fe 23 B 3 phase occurs during crystallization of Pr 8Fe 86 B 6 amorphous alloy, not during crystallization of Pr 8Fe 86- x Zr x B 6( x =1, 2) amorphous alloys. By analyzing the activation energy of crystallization, the formation of an α Fe/Pr 2Fe 14 B composite microstructure with a coarse grain size in annealed Pr 8Fe 86 B 6 alloy, is attributed to a difficult nucleation and an easy growth for both the α Fe and Pr 2Fe 14 B in the alloy. The addition of Zr can be used to change the crystallization behavior of the α Fe phase in Pr Fe B amorphous alloy, which is helpful to reduce the grain size for the α Fe phase.
文摘Bulk amorphous crystal and microcrystal for Pr60Cu(20-x)Ni10Al10Fex (x=0, 8, 15, 20) with the diameter of Φ 2～6 mm were manufactured by electric arc smelting, high frequency heating and copper mold upper suction casting, and its structure was analyzed by X-ray diffract meter. It showed soft magnetic characteristic gradually when Fe content in it was up to 8%. The material was applied to magnetic-electric sensor as key component, output signal of which was measured with the change of Fe content. It shows that the signal changes from weak to strong with the increase of Fe content and presents the largest peak value when Fe is replaced by Cu completely.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51872290,51702322,and 51802307)the National Key Research and Development Program of China(Grant No.2016YFB1102301)
文摘A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes(LDs) is conducted for the thermal lensing compensation. The analyses of the thermal distribution and thermal focal length show that the bonding rod possesses a high cooling efficiency and weak thermal lensing effect compared with the conventional Er,Pr:GYSGG rod. Moreover, the laser characteristics of maximum output power, slope efficiency, and laser beam quality of the bonding rod with concave end-faces operated at 2.79 μm are improved under the high-repetition-rate operation. A maximum output power of 13.96 W is achieved at 150-Hz and 200-μs pulse width,corresponding to a slope efficiency of 17.7% and an electrical-to-optical efficiency of 12.9%. All results suggest that the combination of thermal bonding and concave end-face is a suitable structure for thermal lensing compensation.
文摘Fluorescence decay curves of the 3P0 and 1D2 manifolds in Pr 3+ doped PbWO4 crystal were measured at room temperature and fluorescence lifetimes of both manifolds were estimated. Combining with the radiative lifetimes of the manifolds calculated on the basis of the modified J-O theory, the main mechanisms for the fluorescence quenching of the manifolds were analyzed. The multi-phonon relaxation and the cross-relaxation energy transfer are the major reasons for the fluorescence quenching of the 3P0 and 1D2 manifolds, respectively. The Inokuti-Hirayama model was used to analyze the fluorescence decay curve of the 1D2 manifold and the cross-relaxation of dipole-dipole interaction was confirmed. Consequently, the 3P0 manifold is more favorable as an upper laser level than the 1D2 manifold.
文摘The single crystal of GdP 5O 14 :Sm 3+ ,Pr 3+ (GdPP:Sm,Pr) was grown by the hydrothermal method. The crystal belongs to the monoclinic space group P2 1/ C by X ray powder diffraction results. The dependence of Pr 3+ ion concentration in GdPP:Sm,Pr crystals on the emission intensity of 4 G 5/2 → 6 H 7/2 transitions of Sm 3+ ion and the energy transfer between Sm 3+ and Pr 3+ ions have been investigated and discussed.
文摘The 3μm laser emission of Er 3+ ( 4 I 11/2 → 4 I 13/2 )in the YAG crystal is,in principle,selfsaturation transition,the lifetime of the upper laser level( 4 I 11/2 )being smaller than that of the olwer one( 4 I 13/2 ).The effect of the selfsaturation limit the laser output. In present work,for the first time,we report on the investigation of the utility of Pr 3+ as a sensitizer of Er 3+ ion,using Pr 3+ 4 f 2-4 f5d transition.The radiation emission from 4f5d configuration of Pr 3+ ion have been observed in the YAG∶Pr 3+ crystal.This shows that under suitable conditions this radiant process can compete successfully by non radiative decay to the 4 f configuration.Using Er 3+ Pr 3 codoped YAG it is possible to predict the position of the lowest 4 f 2-4 f5d absorption bands of Pr 3+ ion in the ultraviolet range and to present the occurrence of the energy transfer from Pr 3+ to Er 3+ ion.By xenon flash lamp pumped 2.93μm laser action in the YAG∶(Er 3+ ,Pr 3+ ) crystals was demonstrated at room temperature.
