This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3+-doped solid-state crystals mainly on cubic crystals with 99.99% puri...This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3+-doped solid-state crystals mainly on cubic crystals with 99.99% purity which could be extended to laser ceramics of the same composition.展开更多
Phosphate glass samples with various Yb2O3 and Er2O3 contents were synthesized by the conventional melt quenching technique and characterized by X-ray diffraction,IR absorption spectroscopy and Raman scattering spectr...Phosphate glass samples with various Yb2O3 and Er2O3 contents were synthesized by the conventional melt quenching technique and characterized by X-ray diffraction,IR absorption spectroscopy and Raman scattering spectroscopy.The absorption,emission spectra and fluorescence decay studies were carried out both at low and room temperatures.Results showed the existence of several sites occupied by the rare earth ions in the phosphate glass.Up-conversion and cooperative fluorescence were also discussed.展开更多
The energy transfer and cooperation upconversion processes are investigated in Yb^(3+)/Er^(3+) codoped phosphate glass.Based on the measured curves of output power versus incident power,the laser and spectroscopic par...The energy transfer and cooperation upconversion processes are investigated in Yb^(3+)/Er^(3+) codoped phosphate glass.Based on the measured curves of output power versus incident power,the laser and spectroscopic parameters of the glass are fitted and analyzed.We focus on the resonant energy transfer constant k from Yb^(3+) to Er^(3+) as well as the cooperation upconversion coefficient C_(up) from ~4I_(13/2) of Er^(3+).The fitted k and C_(up) can give almost the same results for different thicknesses of glass disk with the same doping concentrations.The determination of these parameters is helpful for the development of Yb^(3+)/Er^(3+) codoped laser glass.展开更多
Two topics were focused.The first one was about the gamma-ray scintillator,Pr3+:Lu3Al5O12(LuAG) .The second one was about neutron scintillator,Ce3+:6LiCaAlF6 and Eu2+:6LiCaAlF6(6LiCAF) .Those scintillators have been d...Two topics were focused.The first one was about the gamma-ray scintillator,Pr3+:Lu3Al5O12(LuAG) .The second one was about neutron scintillator,Ce3+:6LiCaAlF6 and Eu2+:6LiCaAlF6(6LiCAF) .Those scintillators have been developed very recently for modern imaging appli-cations in the medical and homeland security fields.In both cases,the rare earth ions are playing the crucial role as emission centers.Pr3+ in LuAG provided fast 5d→4f transition providing noticeably shorter decay time than that of Ce3+.Among several candidate hosts,LuAG showed the best performance.Bulk crystal growth,basic scintillation properties,two-dimensional gamma-ray imaging and positron emission mammography(PEM) application were demonstrated.Due to the international situation,the homeland security was compromized by illicit traffic of explosives,drugs,nuclear materials,etc.and the ways to its improvement became an important R&D topic.For this purpose the Ce and Eu doped LiCAF ap-peared competitive candidates.Especially,when substitution of 3He neutron detectors was considered,the discrimination ability of gamma-ray from alpha-ray was important.Bulk crystal growth,basic scintillation properties and two-dimensional neutron imaging were demonstrated.展开更多
Yb-Er codoped Na_2O-Al_2O_3-P_2O_5-xSiO_2 glasses containing 0-20 tool% SiO_2 were prepared successfully. The addition of SiO_2 to the phosphate glass not only lengthens the bond between p^(5+)and non-bridging oxygen ...Yb-Er codoped Na_2O-Al_2O_3-P_2O_5-xSiO_2 glasses containing 0-20 tool% SiO_2 were prepared successfully. The addition of SiO_2 to the phosphate glass not only lengthens the bond between p^(5+)and non-bridging oxygen but also reduces the number of P=O bond.In contrast with silicate glass in which there is only four-fold coordinated Si^(4+),most probably there coexist [SiO_4] tetrahedron and [SiO_6] octahedron in our glasses.Within the range of 0-20 tool% SiO_2 addition,the stimulated emission cross-section of Er^(3+) ion only decreases no more than 10%.The Judd-Ofelt intensity parameters of Er^(3+),Ω_2 does riot change greatly,butΩ_4 andΩ_6 decrease obviously with increasing SiO_2 addition,because the bond between Er^(3+) and O^(2-)is more strongly covalently bonded.展开更多
文摘This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3+-doped solid-state crystals mainly on cubic crystals with 99.99% purity which could be extended to laser ceramics of the same composition.
文摘Phosphate glass samples with various Yb2O3 and Er2O3 contents were synthesized by the conventional melt quenching technique and characterized by X-ray diffraction,IR absorption spectroscopy and Raman scattering spectroscopy.The absorption,emission spectra and fluorescence decay studies were carried out both at low and room temperatures.Results showed the existence of several sites occupied by the rare earth ions in the phosphate glass.Up-conversion and cooperative fluorescence were also discussed.
基金supported by the International Cooperation Project of Shanghai Municipal Science and Technology Commission under Grant No.05S207103.
文摘The energy transfer and cooperation upconversion processes are investigated in Yb^(3+)/Er^(3+) codoped phosphate glass.Based on the measured curves of output power versus incident power,the laser and spectroscopic parameters of the glass are fitted and analyzed.We focus on the resonant energy transfer constant k from Yb^(3+) to Er^(3+) as well as the cooperation upconversion coefficient C_(up) from ~4I_(13/2) of Er^(3+).The fitted k and C_(up) can give almost the same results for different thicknesses of glass disk with the same doping concentrations.The determination of these parameters is helpful for the development of Yb^(3+)/Er^(3+) codoped laser glass.
基金Project supported by Japan Science and Technology Agency,Regional Research and Development Resources Utilization Program,Ministry of Education,Culture,Sports,Science and Technology of Japanese government,Grant-in-Aid for Young Scientists (A)the joint project between JSPS and ASCR (19686001 (AY))+2 种基金Czech GAAV Project (M100100910)the Funding Program for Next Generation World-Leading ResearchersJapan Society for Promotion of Science
文摘Two topics were focused.The first one was about the gamma-ray scintillator,Pr3+:Lu3Al5O12(LuAG) .The second one was about neutron scintillator,Ce3+:6LiCaAlF6 and Eu2+:6LiCaAlF6(6LiCAF) .Those scintillators have been developed very recently for modern imaging appli-cations in the medical and homeland security fields.In both cases,the rare earth ions are playing the crucial role as emission centers.Pr3+ in LuAG provided fast 5d→4f transition providing noticeably shorter decay time than that of Ce3+.Among several candidate hosts,LuAG showed the best performance.Bulk crystal growth,basic scintillation properties,two-dimensional gamma-ray imaging and positron emission mammography(PEM) application were demonstrated.Due to the international situation,the homeland security was compromized by illicit traffic of explosives,drugs,nuclear materials,etc.and the ways to its improvement became an important R&D topic.For this purpose the Ce and Eu doped LiCAF ap-peared competitive candidates.Especially,when substitution of 3He neutron detectors was considered,the discrimination ability of gamma-ray from alpha-ray was important.Bulk crystal growth,basic scintillation properties and two-dimensional neutron imaging were demonstrated.
基金supported by the International Cooperation Project of Shanghai Municipal Science Technology Commission under Grant No.05S207103.
文摘Yb-Er codoped Na_2O-Al_2O_3-P_2O_5-xSiO_2 glasses containing 0-20 tool% SiO_2 were prepared successfully. The addition of SiO_2 to the phosphate glass not only lengthens the bond between p^(5+)and non-bridging oxygen but also reduces the number of P=O bond.In contrast with silicate glass in which there is only four-fold coordinated Si^(4+),most probably there coexist [SiO_4] tetrahedron and [SiO_6] octahedron in our glasses.Within the range of 0-20 tool% SiO_2 addition,the stimulated emission cross-section of Er^(3+) ion only decreases no more than 10%.The Judd-Ofelt intensity parameters of Er^(3+),Ω_2 does riot change greatly,butΩ_4 andΩ_6 decrease obviously with increasing SiO_2 addition,because the bond between Er^(3+) and O^(2-)is more strongly covalently bonded.
