In this paper, optical spectra of LiYF4 single crystals doped with Tm3＋ ions of various concentrations are reported. The emission intensity at 1.8 ktm first increases with increasing Tm3＋ concentration, and reaches ...In this paper, optical spectra of LiYF4 single crystals doped with Tm3＋ ions of various concentrations are reported. The emission intensity at 1.8 ktm first increases with increasing Tm3＋ concentration, and reaches a maximum value when the concentration of Tm3＋ is about 1.28 mol%, then it decreases rapidly as the concentration of Tm3＋ further increases to 3.49 mol%. The emission lifetime at 1.8 p.m also shows a similar tendency to the emission intensity. The maximum lifetime of 1.8 μm is measured to be 17.68 ms for the sample doped with Tm3＋ of 1.28 mol%. The emission cross section of 3F4 level is calculated. The maximum reaches 3.76 × 10 -21 cm2 at 1909 nm. The cross relaxation （3H6, 3H4 →3 F4, 3F4） between Tm3＋ ions and the concentration quenching effect are mainly attributed to the change of emission with Tm3＋ concentration. The largest quantum efficiency between Tm3＋ ions is estimated to be ,-147% from the measured lifetime and calculated radiative lifetime. All the results suggest that the Tm3＋/LiYF4 single crystal may have potential applications in 2 μm mid-infrared lasers.展开更多
[ Objective] The research aimed to study response rule of the M. aeruginosa fluorescence on the biological toxicity of HgCI2. [ Method ] M. aeruginosa as material, fluorescence intensity at its best excitation and emi...[ Objective] The research aimed to study response rule of the M. aeruginosa fluorescence on the biological toxicity of HgCI2. [ Method ] M. aeruginosa as material, fluorescence intensity at its best excitation and emission wavelengths as measured indicator, influence of the HgCI2 at different mass concentrations on fluorescence intensity of the M. aeruginosa was discussed initially. [ Result] HgCI2 at different mass concentrations had different influences on M. aeruginosa. HgCI2 at low concentration （0.002 -0.004 mg/L）could promote photosynthesis of the M. aeruginosa. It showed as fluorescence value of the algae liquid becoming smaller. 0.010 -0.400 mg/L of HgCI2 inhibited photosynthesis of the M. aeruginosa. It showed as fluorescence value of the algae liquid becoming bigger. Moreover, inhibition effect increased as HgCI2 concentration rose, showing a positive correlation between HgCI2 concentration and toxicity （ R 2 = 0.963 5 ）. [ Conclusion ] The research provided new theoretical basis for quickly measuring water toxicity.展开更多
We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles ...We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles are fabricated to optimize the output power and spatial-mode performance. The best devices exhibit single-spatial-mode operation with room-temperature output power up to 350？mW in continuous-wave mode at an emission wavelength around 2.0？μm with a very small far-field lateral divergence angle, which is beyond state of the art in terms of single-spatial-mode output power.展开更多
Ho3＋/yb3＋ co-doped LiYF4 single crystals with various Yb3＋ concentrations and ,-~ 0.98 mol% Ho3＋ concentration are grown by the Bridgman method under the conditions of taking LiF and YF3 as raw materials and a tem...Ho3＋/yb3＋ co-doped LiYF4 single crystals with various Yb3＋ concentrations and ,-~ 0.98 mol% Ho3＋ concentration are grown by the Bridgman method under the conditions of taking LiF and YF3 as raw materials and a temperature gradient （40 ~C/cm-50 ~C/cm） for the solid-liquid interface. The luminescent performances of the crystals are investigated through emission spectra, infrared transmittance spectrum, emission cross section, and decay curves under excitation by 980 nm. Compared with the Ho3＋ single-doped LiYF4 crystal, the Ho3＋/yb3＋ co-doped tiYf4 single crystal has an obviously enhanced emission band from 1850 nm to 2150 nm observed when excited by a 980-nm diode laser. The energy transfer from Yb3＋ to Ho3＋ and the optimum fluorescence emission around 2.0 p-m of Ho3＋ ions are investigated. The maximum emission cross section of the above sample at 2.0 p.m is calculated to be 1.08 × 10-20 cm2 for the LiYF4 single crystal of 1-mol% Ho3＋ and 6-mo1% Yb3＋ according to the measured absorption spectrum. The high energy transfer efficiency of 88.9% from Yb3＋ to Ho3＋ ion in the sample co-doped by Ho3＋ （1 mol%） and Yb3＋ （8 tool%） demonstrates that the Yb3＋ ions can efficiently sensitize the Ho3＋ ions.展开更多
Reactions of Cd（OAC）2·2H2O with m-thioacetatebenzoic acid（H2L） and 1,10-phenanthroline（phen） give rise to a metal-organic framework,[CdL（phen）]n（1）.X-ray single-crystal diffraction reveals that 1 crysta...Reactions of Cd（OAC）2·2H2O with m-thioacetatebenzoic acid（H2L） and 1,10-phenanthroline（phen） give rise to a metal-organic framework,[CdL（phen）]n（1）.X-ray single-crystal diffraction reveals that 1 crystallizes in the monoclinic system,space group C2/c,with a= 25.7099（5）,b=10.3872（2）,c=19.1820（4）,β=131.114（1）°,V=3859.4（1）3,Mr=502.80,Z= 8,F（000）=2000,μ=1.271 mm-1,Dc=1.731 g·cm-3,the final R=0.0226 and wR=0.0559 for 3817 observed reflections（Ⅰ〉 2σ（Ⅰ））.1 displays a 1D double-strand chain structure with crab-like dinuclear subunits,and extends into a 3D network by π-π interactions and C-H···O hydrogen bonds.Photoluminescence studies reveal that it displays intense structure-related fluorescent emission bands（λex=342 nm） at 370.5 and 389 nm in the solid state at room temperature.展开更多
Na_(5)Y_(9)F_(32) single crystals doped with ~0.8-mol% Ho^(3+),~1-mol% Tm^(3+),and various Er^(3+) ion concentrations were prepared by a modified Bridgman method.The effects of Er^(3+)ion concentration on 2.0-μm emis...Na_(5)Y_(9)F_(32) single crystals doped with ~0.8-mol% Ho^(3+),~1-mol% Tm^(3+),and various Er^(3+) ion concentrations were prepared by a modified Bridgman method.The effects of Er^(3+)ion concentration on 2.0-μm emission excited by an800-nm laser diode were investigated with the help of their spectroscopic properties.The intensity of 2.0-μm emission reached to maximum when the Er^(3+) ion concentration was ~1 mol%.The energy transfer mechanisms between Er^(3+),Ho^(3+),and Tm^(3+) ions were identified from the change of the absorption spectra,the emission spectra,and the measured decay curves.The maximum 2.0-μm emission cross section of the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystal reached 5.26 × 10^(-21) cm^(2).The gain cross section spectra were calculated according to the absorption and emission cross section spectra.The cross section for ~2.0-μm emission became a positive gain once the inversion level of population was reached 30%.The energy transfer efficiency was further increased by 11.81% through the incorporation of Er^(3+) ion into Ho^(3+)/Tm^(3+) system estimated from the measured lifetimes of Ho^(3+)/Tm^(3+)-and Er^(3+)/Ho^(3+)/Tm^(3+)-doped Na_(5)Y_(9)F_(32)single crystals.The present results illustrated that the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystals can be used as promising candidate for 2.0-μm laser.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472125 and 51272109)the Natural Science Foundation of Ningbo City,China(Grant No.201401A6105016)K.C.Wong Magna Fund in Ningbo University,China(Grant No.NBUWC001)
文摘In this paper, optical spectra of LiYF4 single crystals doped with Tm3＋ ions of various concentrations are reported. The emission intensity at 1.8 ktm first increases with increasing Tm3＋ concentration, and reaches a maximum value when the concentration of Tm3＋ is about 1.28 mol%, then it decreases rapidly as the concentration of Tm3＋ further increases to 3.49 mol%. The emission lifetime at 1.8 p.m also shows a similar tendency to the emission intensity. The maximum lifetime of 1.8 μm is measured to be 17.68 ms for the sample doped with Tm3＋ of 1.28 mol%. The emission cross section of 3F4 level is calculated. The maximum reaches 3.76 × 10 -21 cm2 at 1909 nm. The cross relaxation （3H6, 3H4 →3 F4, 3F4） between Tm3＋ ions and the concentration quenching effect are mainly attributed to the change of emission with Tm3＋ concentration. The largest quantum efficiency between Tm3＋ ions is estimated to be ,-147% from the measured lifetime and calculated radiative lifetime. All the results suggest that the Tm3＋/LiYF4 single crystal may have potential applications in 2 μm mid-infrared lasers.
基金Supported by National 863 Item,China (2007AA092201)
文摘[ Objective] The research aimed to study response rule of the M. aeruginosa fluorescence on the biological toxicity of HgCI2. [ Method ] M. aeruginosa as material, fluorescence intensity at its best excitation and emission wavelengths as measured indicator, influence of the HgCI2 at different mass concentrations on fluorescence intensity of the M. aeruginosa was discussed initially. [ Result] HgCI2 at different mass concentrations had different influences on M. aeruginosa. HgCI2 at low concentration （0.002 -0.004 mg/L）could promote photosynthesis of the M. aeruginosa. It showed as fluorescence value of the algae liquid becoming smaller. 0.010 -0.400 mg/L of HgCI2 inhibited photosynthesis of the M. aeruginosa. It showed as fluorescence value of the algae liquid becoming bigger. Moreover, inhibition effect increased as HgCI2 concentration rose, showing a positive correlation between HgCI2 concentration and toxicity （ R 2 = 0.963 5 ）. [ Conclusion ] The research provided new theoretical basis for quickly measuring water toxicity.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB643903 and 2013CB932904the National Natural Science Foundation of China under Grant Nos 61435012 and 61290303the Strategic Priority Research Program(B) of the Chinese Academy of Sciences under Grant No XDB01010200
文摘We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles are fabricated to optimize the output power and spatial-mode performance. The best devices exhibit single-spatial-mode operation with room-temperature output power up to 350？mW in continuous-wave mode at an emission wavelength around 2.0？μm with a very small far-field lateral divergence angle, which is beyond state of the art in terms of single-spatial-mode output power.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472125 and 51272109)the K.C.Wong Magna Fund in Ningbo University,China(Grant No.NBUWC001)
文摘Ho3＋/yb3＋ co-doped LiYF4 single crystals with various Yb3＋ concentrations and ,-~ 0.98 mol% Ho3＋ concentration are grown by the Bridgman method under the conditions of taking LiF and YF3 as raw materials and a temperature gradient （40 ~C/cm-50 ~C/cm） for the solid-liquid interface. The luminescent performances of the crystals are investigated through emission spectra, infrared transmittance spectrum, emission cross section, and decay curves under excitation by 980 nm. Compared with the Ho3＋ single-doped LiYF4 crystal, the Ho3＋/yb3＋ co-doped tiYf4 single crystal has an obviously enhanced emission band from 1850 nm to 2150 nm observed when excited by a 980-nm diode laser. The energy transfer from Yb3＋ to Ho3＋ and the optimum fluorescence emission around 2.0 p-m of Ho3＋ ions are investigated. The maximum emission cross section of the above sample at 2.0 p.m is calculated to be 1.08 × 10-20 cm2 for the LiYF4 single crystal of 1-mol% Ho3＋ and 6-mo1% Yb3＋ according to the measured absorption spectrum. The high energy transfer efficiency of 88.9% from Yb3＋ to Ho3＋ ion in the sample co-doped by Ho3＋ （1 mol%） and Yb3＋ （8 tool%） demonstrates that the Yb3＋ ions can efficiently sensitize the Ho3＋ ions.
基金The National Natural Science Foundation of China(No.51472162,61605115)Shanghai Sailing Project(No.15YF1411800)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(No.TP2014061)
文摘Reactions of Cd（OAC）2·2H2O with m-thioacetatebenzoic acid（H2L） and 1,10-phenanthroline（phen） give rise to a metal-organic framework,[CdL（phen）]n（1）.X-ray single-crystal diffraction reveals that 1 crystallizes in the monoclinic system,space group C2/c,with a= 25.7099（5）,b=10.3872（2）,c=19.1820（4）,β=131.114（1）°,V=3859.4（1）3,Mr=502.80,Z= 8,F（000）=2000,μ=1.271 mm-1,Dc=1.731 g·cm-3,the final R=0.0226 and wR=0.0559 for 3817 observed reflections（Ⅰ〉 2σ（Ⅰ））.1 displays a 1D double-strand chain structure with crab-like dinuclear subunits,and extends into a 3D network by π-π interactions and C-H···O hydrogen bonds.Photoluminescence studies reveal that it displays intense structure-related fluorescent emission bands（λex=342 nm） at 370.5 and 389 nm in the solid state at room temperature.
基金Project supported by the National Natural Science Foundation of China(Grant No.51772159)the Natural Science Foundation of Zhejiang Province+2 种基金China(Grant No.LZ17E020001)the Natural Science Foundation of Ningbo City(Grant No.202003N4099)K C Wong Magna Fund in Ningbo University。
文摘Na_(5)Y_(9)F_(32) single crystals doped with ~0.8-mol% Ho^(3+),~1-mol% Tm^(3+),and various Er^(3+) ion concentrations were prepared by a modified Bridgman method.The effects of Er^(3+)ion concentration on 2.0-μm emission excited by an800-nm laser diode were investigated with the help of their spectroscopic properties.The intensity of 2.0-μm emission reached to maximum when the Er^(3+) ion concentration was ~1 mol%.The energy transfer mechanisms between Er^(3+),Ho^(3+),and Tm^(3+) ions were identified from the change of the absorption spectra,the emission spectra,and the measured decay curves.The maximum 2.0-μm emission cross section of the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystal reached 5.26 × 10^(-21) cm^(2).The gain cross section spectra were calculated according to the absorption and emission cross section spectra.The cross section for ~2.0-μm emission became a positive gain once the inversion level of population was reached 30%.The energy transfer efficiency was further increased by 11.81% through the incorporation of Er^(3+) ion into Ho^(3+)/Tm^(3+) system estimated from the measured lifetimes of Ho^(3+)/Tm^(3+)-and Er^(3+)/Ho^(3+)/Tm^(3+)-doped Na_(5)Y_(9)F_(32)single crystals.The present results illustrated that the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystals can be used as promising candidate for 2.0-μm laser.
