We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. U...We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.展开更多
The growth of LiNbO3 single crystal with Er^3＋ and Zn^2＋ co-doped using Bridgman method and its characteristic absorption spectra and fluorescence spectra were reported. Large-size crystals initially containing Zn^2...The growth of LiNbO3 single crystal with Er^3＋ and Zn^2＋ co-doped using Bridgman method and its characteristic absorption spectra and fluorescence spectra were reported. Large-size crystals initially containing Zn^2＋ （3%） and Er^3＋ （0.6%） with good optical quality were obtained using optimized conditions such as a growth rate of 0.8- 1.5 mm·h^-1 and a temperature gradient of about 30 - 35℃·cm^-1 across the solid-liquid interface and the sealed platinum crucible. X-ray diffraction and differential thermal analysis （DTA） were used to characterize the crystals. The results indicate that the concentration of Er^3＋ ions in crystals, their absorption intensity, and their fluorescence intensity decrease from the bottom to the top in the crystals. However, for the upper part of the crystal, the up-conversion fluorescence intensity is higher than that of the lower part excited by an 800 or 970 nm pump. The effects of the crystal lattice, their structural defect and their effective segregation of Er^3＋ ions were discussed with respect to the variations of the up-conversion fluorescence intensity.展开更多
The growth of LiNbO3 single crystal with Er^3＋/Zn^2＋ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized con- ditions such ...The growth of LiNbO3 single crystal with Er^3＋/Zn^2＋ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized con- ditions such as growth rate of 0.8 - 1.5 mm · h^- 1, temperature gradient about 30 - 35℃ ·cm^-1 across the solid-liquid interface and sealed platinum, large size crystals containing Zn^2＋ （3%） and Er^3＋ （0.6%） with good optical quality were obtained. X-ray diffraction and DTA were used to characterize the crystals. The results indicate that the concentration of Er^3＋ ions in crystals decrease along the growth direction, the absorption intensity and the fluorescence intensity ions also decrease along the growth direction. of Er^3＋ However, for the upper part crystal, the upconversion fluorescence intensity is higher than that of the lower part crystal excited with 800 or 970 nm pump. The effects of crystal lattice, structure defect and effective segregation of Er^3＋ ions were discussed in respect to the variations were discussed of upconversion fluorescence intensity.展开更多
Single crystal of Li2Zn2（MoO4）3 has been grown from a flux of Li2MoO4 by the top-seeded solution-growth method, and its stnicture was refined by the Rietveld method. It belongs to the orthorhombic system, space grou...Single crystal of Li2Zn2（MoO4）3 has been grown from a flux of Li2MoO4 by the top-seeded solution-growth method, and its stnicture was refined by the Rietveld method. It belongs to the orthorhombic system, space group Pnma with a = 5.1114, b = 10.4906 and c = 17.6172A. Good agreement between the experimental and calculated profile （Rp = 6.69%, Rwp = 9.73% and Rexp = 6.58%） was reached.展开更多
A novel coordination ploymer [{Zn(3-SBA)(2,2′-bipy)(H2O)2}·H2O]n was synthesized by the hydrothermal reaction of 3-Na2SBA, ZnSO4·7H2O and 2,2′-bipy. The structure was characterized by elemental analysis, I...A novel coordination ploymer [{Zn(3-SBA)(2,2′-bipy)(H2O)2}·H2O]n was synthesized by the hydrothermal reaction of 3-Na2SBA, ZnSO4·7H2O and 2,2′-bipy. The structure was characterized by elemental analysis, IR and single crystal X-ray diffraction. The title coordination ploymer crystallized in monoclinic with space group P21, a=0.803 42(18) nm, b=1.501 8(3) nm, c=0.821 13(19) nm, β=109.350(4)°. The coordination polymer has an infinite chain structure and its luminescent property has also been studied. CCDC: 282746.展开更多
LiNbO 3crystal possesses electro optic effect and nonlinear optical effect.Bec ars e it is easy to generate photo damage(photorefractive) for LiNbO 3.This limits i ts application in some fields.When doping 6mol% ZnO o...LiNbO 3crystal possesses electro optic effect and nonlinear optical effect.Bec ars e it is easy to generate photo damage(photorefractive) for LiNbO 3.This limits i ts application in some fields.When doping 6mol% ZnO or 5mol% MgO in LiNbO 3 cry stal to grow Zn∶LiNbO 3 or Mg∶LiNbO 3 crystal,the photo damage resistance ab ility fo these two crystals is two orders of magnitude higher than that of LiNbO 3.We doped 3mol% ZnO and 3mol% MgO to grow Zn∶Mg∶LiNbO 3 crystal and used Fourier spectrophotometer to measure the infrared transmission spectra.The waven umber range to measure the OH - stretched vibration transmission spectra of Zn ∶LiNbO 3,Mg∶LiNbO 3 and Zn∶Mg∶LiNbO 3 crystal is 3200 4000cm -1 .The measurement result is that the OH - stretched vibration absorption peak of Zn( 6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 crystal is at 3535cm -1 (2.83μm),while that of pure LiNbO 3,Zn(3mol%):LiNbO 3 and M g(3mol%):LiNbO 3 is at 3484cm -1 (2.87μm).We take the direct obseration me thod of the focula distortion in crystal to measure the photorefractive threshol d value of these crystals and gained the result that the photorefractive thresho ld value of Zn(6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 increase above two orders of magnitude higher than pure LiNbO 3 crystal and the photorefractive threshold value of Zn(3mol%):LiNbO 3 and Mg(3mol%):LiNbO 3 is a little higher than that of pure LiNbO 3 crystal.The congruent compositio n ratio of LiNbO 3 is Li/Nb=0.946.A part of Nb 5+ take place Li + site to form the intrinsic defect antisite Nb 4+ Li .The charge transport proc ess in LiNbO 3 is due to this kind of intrinsic defect.Especially in high light intensity,the intrinsic defect is important.The quantity that make antisite Nb 4+ Li defect structure disappear when doping ions (Mg 2+ and Zn 2+ ) substitute for all Nb 4+ Li at Li + site is called the thre shold concentration for this impurity ion.At the same time the impurity ion star t to take place Nb site.The photo damage resistance impurity ion is to drive ant i site Nb Li from Li site to normal Nb site so that the OH - absorption peak shifts to 2.83μm from 2.87μm.The fact that the OH - absorption peak of Zn(3m ol%):Mg(3mol%):LiNbO 3 crystal shifts to 2.83μm from 2.87μm and its photo dam age resistance threshold value is two orders of magnitude higher than pure LiNbO 3 crystal shows that above analyse is reasonable.展开更多
ZnO(4mol%),In 2O 3(1mol%)and Fe 2O 3(0.05mol%)were doped in LiNbO 3 and Czochralski method was used to grow Zn∶In∶Fe∶LiNbO 3 crystal.The diameter of the crystal we grew is 30mm.The technology parameter we took is t...ZnO(4mol%),In 2O 3(1mol%)and Fe 2O 3(0.05mol%)were doped in LiNbO 3 and Czochralski method was used to grow Zn∶In∶Fe∶LiNbO 3 crystal.The diameter of the crystal we grew is 30mm.The technology parameter we took is that the axial temperature gradient is 40℃/cm,the growth rate is 1mm/h, the rotation rate is 15-25r/min,the temperature of polarization is 1220℃ and the current density of polarization is 5mA/cm 2.The wafer dimension is 10mm×10mm×3mm and was covered in Li 2CO 3 powder to reduce.The reduction temperature is 500℃ and reduction time is 30 hours. OH - stretch vibration transmission spectra were measured by Fourier infrared spectrophotometer. There are two absorption peaks in OH - spectra of Zn∶In∶Fe∶LiNbO 3,in which one is at 3534cm -1 (2.83μm) and the other is at 3505cm -1 (2.85μm).The peak at 2.85μm is far lower than that at 2.83μm. Because of the threshold effect of Zn 2+ and In 3+ ,the peak at 2.83μm is generated and the peak at 2.85μm is related with Fe 3+ .In LiNbO 3 only doped with Fe,Li + site is taken place by Fe 3+ .When doping Zn 2+ and In 3+ in high concentration,these two ions take place Nb that is at Li site and Fe 3+ substitutes for Nb 5+ at the same time.The interaction between Fe 3+ and OH - make the OH - peak shift to 2.85μm.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No. 51202045）, the Postdoctoral Science Foundation of Heilongjiang Province, China, and the Fundamental Research Funds for the Central Universities of Ministry of Education of China （Grant No. HIT. NSRIF. 2013004）.
文摘We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.
基金Project supported by Scientific Research Fund of Zhejiang Provincial Education Department (20061660)Foundation ofNingbo University (xk200435)
文摘The growth of LiNbO3 single crystal with Er^3＋ and Zn^2＋ co-doped using Bridgman method and its characteristic absorption spectra and fluorescence spectra were reported. Large-size crystals initially containing Zn^2＋ （3%） and Er^3＋ （0.6%） with good optical quality were obtained using optimized conditions such as a growth rate of 0.8- 1.5 mm·h^-1 and a temperature gradient of about 30 - 35℃·cm^-1 across the solid-liquid interface and the sealed platinum crucible. X-ray diffraction and differential thermal analysis （DTA） were used to characterize the crystals. The results indicate that the concentration of Er^3＋ ions in crystals, their absorption intensity, and their fluorescence intensity decrease from the bottom to the top in the crystals. However, for the upper part of the crystal, the up-conversion fluorescence intensity is higher than that of the lower part excited by an 800 or 970 nm pump. The effects of the crystal lattice, their structural defect and their effective segregation of Er^3＋ ions were discussed with respect to the variations of the up-conversion fluorescence intensity.
文摘The growth of LiNbO3 single crystal with Er^3＋/Zn^2＋ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized con- ditions such as growth rate of 0.8 - 1.5 mm · h^- 1, temperature gradient about 30 - 35℃ ·cm^-1 across the solid-liquid interface and sealed platinum, large size crystals containing Zn^2＋ （3%） and Er^3＋ （0.6%） with good optical quality were obtained. X-ray diffraction and DTA were used to characterize the crystals. The results indicate that the concentration of Er^3＋ ions in crystals decrease along the growth direction, the absorption intensity and the fluorescence intensity ions also decrease along the growth direction. of Er^3＋ However, for the upper part crystal, the upconversion fluorescence intensity is higher than that of the lower part crystal excited with 800 or 970 nm pump. The effects of crystal lattice, structure defect and effective segregation of Er^3＋ ions were discussed in respect to the variations were discussed of upconversion fluorescence intensity.
基金the National Natural Science Foundation of China (No. 50672123)
文摘Single crystal of Li2Zn2（MoO4）3 has been grown from a flux of Li2MoO4 by the top-seeded solution-growth method, and its stnicture was refined by the Rietveld method. It belongs to the orthorhombic system, space group Pnma with a = 5.1114, b = 10.4906 and c = 17.6172A. Good agreement between the experimental and calculated profile （Rp = 6.69%, Rwp = 9.73% and Rexp = 6.58%） was reached.
文摘A novel coordination ploymer [{Zn(3-SBA)(2,2′-bipy)(H2O)2}·H2O]n was synthesized by the hydrothermal reaction of 3-Na2SBA, ZnSO4·7H2O and 2,2′-bipy. The structure was characterized by elemental analysis, IR and single crystal X-ray diffraction. The title coordination ploymer crystallized in monoclinic with space group P21, a=0.803 42(18) nm, b=1.501 8(3) nm, c=0.821 13(19) nm, β=109.350(4)°. The coordination polymer has an infinite chain structure and its luminescent property has also been studied. CCDC: 282746.
文摘LiNbO 3crystal possesses electro optic effect and nonlinear optical effect.Bec ars e it is easy to generate photo damage(photorefractive) for LiNbO 3.This limits i ts application in some fields.When doping 6mol% ZnO or 5mol% MgO in LiNbO 3 cry stal to grow Zn∶LiNbO 3 or Mg∶LiNbO 3 crystal,the photo damage resistance ab ility fo these two crystals is two orders of magnitude higher than that of LiNbO 3.We doped 3mol% ZnO and 3mol% MgO to grow Zn∶Mg∶LiNbO 3 crystal and used Fourier spectrophotometer to measure the infrared transmission spectra.The waven umber range to measure the OH - stretched vibration transmission spectra of Zn ∶LiNbO 3,Mg∶LiNbO 3 and Zn∶Mg∶LiNbO 3 crystal is 3200 4000cm -1 .The measurement result is that the OH - stretched vibration absorption peak of Zn( 6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 crystal is at 3535cm -1 (2.83μm),while that of pure LiNbO 3,Zn(3mol%):LiNbO 3 and M g(3mol%):LiNbO 3 is at 3484cm -1 (2.87μm).We take the direct obseration me thod of the focula distortion in crystal to measure the photorefractive threshol d value of these crystals and gained the result that the photorefractive thresho ld value of Zn(6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 increase above two orders of magnitude higher than pure LiNbO 3 crystal and the photorefractive threshold value of Zn(3mol%):LiNbO 3 and Mg(3mol%):LiNbO 3 is a little higher than that of pure LiNbO 3 crystal.The congruent compositio n ratio of LiNbO 3 is Li/Nb=0.946.A part of Nb 5+ take place Li + site to form the intrinsic defect antisite Nb 4+ Li .The charge transport proc ess in LiNbO 3 is due to this kind of intrinsic defect.Especially in high light intensity,the intrinsic defect is important.The quantity that make antisite Nb 4+ Li defect structure disappear when doping ions (Mg 2+ and Zn 2+ ) substitute for all Nb 4+ Li at Li + site is called the thre shold concentration for this impurity ion.At the same time the impurity ion star t to take place Nb site.The photo damage resistance impurity ion is to drive ant i site Nb Li from Li site to normal Nb site so that the OH - absorption peak shifts to 2.83μm from 2.87μm.The fact that the OH - absorption peak of Zn(3m ol%):Mg(3mol%):LiNbO 3 crystal shifts to 2.83μm from 2.87μm and its photo dam age resistance threshold value is two orders of magnitude higher than pure LiNbO 3 crystal shows that above analyse is reasonable.
文摘ZnO(4mol%),In 2O 3(1mol%)and Fe 2O 3(0.05mol%)were doped in LiNbO 3 and Czochralski method was used to grow Zn∶In∶Fe∶LiNbO 3 crystal.The diameter of the crystal we grew is 30mm.The technology parameter we took is that the axial temperature gradient is 40℃/cm,the growth rate is 1mm/h, the rotation rate is 15-25r/min,the temperature of polarization is 1220℃ and the current density of polarization is 5mA/cm 2.The wafer dimension is 10mm×10mm×3mm and was covered in Li 2CO 3 powder to reduce.The reduction temperature is 500℃ and reduction time is 30 hours. OH - stretch vibration transmission spectra were measured by Fourier infrared spectrophotometer. There are two absorption peaks in OH - spectra of Zn∶In∶Fe∶LiNbO 3,in which one is at 3534cm -1 (2.83μm) and the other is at 3505cm -1 (2.85μm).The peak at 2.85μm is far lower than that at 2.83μm. Because of the threshold effect of Zn 2+ and In 3+ ,the peak at 2.83μm is generated and the peak at 2.85μm is related with Fe 3+ .In LiNbO 3 only doped with Fe,Li + site is taken place by Fe 3+ .When doping Zn 2+ and In 3+ in high concentration,these two ions take place Nb that is at Li site and Fe 3+ substitutes for Nb 5+ at the same time.The interaction between Fe 3+ and OH - make the OH - peak shift to 2.85μm.
