The photoluminescence(PL) properties of Ca4YO(BO3)3 doped with Bi3+,Dy3+,and Pr3+ ions were investigated.These compounds were prepared using a typical solid-state reaction.The excitation and emission spectra were meas...The photoluminescence(PL) properties of Ca4YO(BO3)3 doped with Bi3+,Dy3+,and Pr3+ ions were investigated.These compounds were prepared using a typical solid-state reaction.The excitation and emission spectra were measured using a spectrofluorometer.For Ca4YO(BO3)3:Bi3+,the excitation spectrum showed the bands at about 228,309,and 370 nm which correspond to the 1S0→1P1 transition and the 1S0→3P1 transition of Bi3+ ions.The emission band at 390 nm corresponded to the 3P1→1S0 transition of Bi3+ ions.For Ca4YO(...展开更多
Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re...Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.展开更多
Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physica...Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.展开更多
Polycrystalline powders of title compound were prepared by solid state reaction at lower temperature. The exitation and emmission spectra of the system were recorded and discussed. The results showed that there occurs...Polycrystalline powders of title compound were prepared by solid state reaction at lower temperature. The exitation and emmission spectra of the system were recorded and discussed. The results showed that there occurs an energy transfer from Gd 3+ to Eu 3+ . The luminescence intensity of Eu 3+ was found increased with increasing of Gd 3+ concentration. However, Sm 3+ had a quenching influence on the luminescence of Eu 3+ .展开更多
Ca 4YO(BO 3) 3(YCOB) which possesses good NLO properties and chemical stability,is an excellent candidate for frequency conversion crystals to produce green and blue light (SHG and THG of Nd∶YAG laser).In this paper,...Ca 4YO(BO 3) 3(YCOB) which possesses good NLO properties and chemical stability,is an excellent candidate for frequency conversion crystals to produce green and blue light (SHG and THG of Nd∶YAG laser).In this paper,preparation of the feed material and the vertical Bridgman growth condition for YCOB crystal is reported for the first time to our knowledge. YCOB crystals have been grown from the feed materials composed of Y 2O 3(4N),CaCO 3/CaO (A.R.) and H 3BO 3/B 2O 3(4N)by vertical Bridgman method.Since Ca 4YO(BO 3) 3 melts congruently,the feed material should be prepared in the stoichiometric composition.The evaporation of B 2O 3 at high temperature and the hygroscopicity of CaO,B 2O 3 and Y 2O 3 were carefully considered.It was showed by experiments that the feed material prepared by directly and thoroughly mixing together stoichiometric amount of Y 2O 3,CaO and B 2O 3 is suitable for the Bridgman growth of YCOB crystal.The melting point of YCOB crystal is 1510℃,and Pt crucible less than 1.0mm thick was chosen.The temperature of the furnace was controlled from 1560℃ to 1650℃.Owing to the extremely high melting points of both Y 2O 3 and CaO,the feed material had been heated at the above temperature for more than 10 hours before growth so that it melts thoroughly.The growth rate of 0.2-0.6mm/h and the temperature gradient near the solid-liquid interface of 40-60°C/cm were chosen.The Crack free and transparent YCOB crystals with 25mm in diameter and 50mm long have been grown in near sealed Pt crucibles under the above growth condition,which suggests that the vertical Bridgman method is suitable for the growth of YCOB crystal.展开更多
基金supported by Scientific Research Foundation for Returned Scholars of Ministry of Education of China (20071108)
文摘The photoluminescence(PL) properties of Ca4YO(BO3)3 doped with Bi3+,Dy3+,and Pr3+ ions were investigated.These compounds were prepared using a typical solid-state reaction.The excitation and emission spectra were measured using a spectrofluorometer.For Ca4YO(BO3)3:Bi3+,the excitation spectrum showed the bands at about 228,309,and 370 nm which correspond to the 1S0→1P1 transition and the 1S0→3P1 transition of Bi3+ ions.The emission band at 390 nm corresponded to the 3P1→1S0 transition of Bi3+ ions.For Ca4YO(...
文摘Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.
文摘Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.
文摘Polycrystalline powders of title compound were prepared by solid state reaction at lower temperature. The exitation and emmission spectra of the system were recorded and discussed. The results showed that there occurs an energy transfer from Gd 3+ to Eu 3+ . The luminescence intensity of Eu 3+ was found increased with increasing of Gd 3+ concentration. However, Sm 3+ had a quenching influence on the luminescence of Eu 3+ .
文摘Ca 4YO(BO 3) 3(YCOB) which possesses good NLO properties and chemical stability,is an excellent candidate for frequency conversion crystals to produce green and blue light (SHG and THG of Nd∶YAG laser).In this paper,preparation of the feed material and the vertical Bridgman growth condition for YCOB crystal is reported for the first time to our knowledge. YCOB crystals have been grown from the feed materials composed of Y 2O 3(4N),CaCO 3/CaO (A.R.) and H 3BO 3/B 2O 3(4N)by vertical Bridgman method.Since Ca 4YO(BO 3) 3 melts congruently,the feed material should be prepared in the stoichiometric composition.The evaporation of B 2O 3 at high temperature and the hygroscopicity of CaO,B 2O 3 and Y 2O 3 were carefully considered.It was showed by experiments that the feed material prepared by directly and thoroughly mixing together stoichiometric amount of Y 2O 3,CaO and B 2O 3 is suitable for the Bridgman growth of YCOB crystal.The melting point of YCOB crystal is 1510℃,and Pt crucible less than 1.0mm thick was chosen.The temperature of the furnace was controlled from 1560℃ to 1650℃.Owing to the extremely high melting points of both Y 2O 3 and CaO,the feed material had been heated at the above temperature for more than 10 hours before growth so that it melts thoroughly.The growth rate of 0.2-0.6mm/h and the temperature gradient near the solid-liquid interface of 40-60°C/cm were chosen.The Crack free and transparent YCOB crystals with 25mm in diameter and 50mm long have been grown in near sealed Pt crucibles under the above growth condition,which suggests that the vertical Bridgman method is suitable for the growth of YCOB crystal.
