Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission sp...Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.展开更多
采用提拉法生长了不同Li/Nb(Li/Nb=0.94,1.05,1.20 and 1.38)的Mg:Ho:LiNbO3单晶.测试了Mg:Ho:LiNbO3晶体的双折射梯度和抗光损伤能力.实验结果表明:Li/Nb=1.38的Mg:Ho:LiNbO3晶体有较好的光学均匀性,随着Li/Nb比的增加,晶体抗光损伤能...采用提拉法生长了不同Li/Nb(Li/Nb=0.94,1.05,1.20 and 1.38)的Mg:Ho:LiNbO3单晶.测试了Mg:Ho:LiNbO3晶体的双折射梯度和抗光损伤能力.实验结果表明:Li/Nb=1.38的Mg:Ho:LiNbO3晶体有较好的光学均匀性,随着Li/Nb比的增加,晶体抗光损伤能力增强,并分析了其抗光损伤能力增强的机理.结合LiNbO3晶体的锂空位缺陷模型和占位机制解释了相关实验结果.展开更多
A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distorti...A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distortion method, and their response time and exponential gain coefficient were tested by two-beam coupling experiment. Besides, the effective carrier concentration has been calculated. The results showed that the absorption edges of reduced and oxidized crystals are respectively shifted to violet and Einstein compared with those of the growth state crystal. From oxidation state to growth state to reduction state of the samples, the photo scattering resistance ability and response time decrease while the exponential gain coefficient and concentration of effective carriers increase. The reduction treatment was necessary for the Mg：In：Fe：LiNbO3 crystals to enhance their photorefractive properties.展开更多
In 2O 3, MgO and Fe 2O 3 were doped in LiNbO3 and Czochralski method was used to grow In:Mg:Fe:LiNbO 3 crystals. The OH - extension transmission spectra, light scattering resistance ability, two wave coupled dif...In 2O 3, MgO and Fe 2O 3 were doped in LiNbO3 and Czochralski method was used to grow In:Mg:Fe:LiNbO 3 crystals. The OH - extension transmission spectra, light scattering resistance ability, two wave coupled diffraction efficiency and response time of the crystal were measured. Codoping In and Mg in crystal will improve its light scattering resistance ability and response time. Doping In can increase the ability to replace antisite Nb and decrease the doping quantity of Mg. All these are propitious to improve the optical homogeneity of crystal. Doping Fe can improve the photorefractive sensitivity for LiNbO 3 crystal. We discussed the site of In, Mg and Fe in LiNbO 3 crystals and the influence of the absorption peak of OH - transmission spectra on photorefractive property for LiNbO 3 crystal.展开更多
The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. ...The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. Compared with As-grown Mg:Mn:Fe:LiNbO 3, the absorption edge in UV-Vis. absorption spectrum of the oxidized sample and the reduced shifts to the violet and the red, respectively. Reduction increases the absorption of crystals in visible light region. In two-wave coupling experiments, the writing time, maximum diffraction efficiency and the erasure time of crystal samples in the same conditions are determined. The results indicate that oxidation and reduction disposing has great effect on the holographic recording properties of these crystals. The reduced crystal exhibits the fastest response time of 160 s among the crystal series. The mechanism of post-disposing effect on the holographic recording properties of Mg:Mn:Fe:LiNbO 3 crystals are investigated.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
基金Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. DL12AB03)the National Natural Science Founda-tion of China (Grant No. 60777006)
文摘Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.
文摘采用提拉法生长了不同Li/Nb(Li/Nb=0.94,1.05,1.20 and 1.38)的Mg:Ho:LiNbO3单晶.测试了Mg:Ho:LiNbO3晶体的双折射梯度和抗光损伤能力.实验结果表明:Li/Nb=1.38的Mg:Ho:LiNbO3晶体有较好的光学均匀性,随着Li/Nb比的增加,晶体抗光损伤能力增强,并分析了其抗光损伤能力增强的机理.结合LiNbO3晶体的锂空位缺陷模型和占位机制解释了相关实验结果.
基金This work was supported by the Harbin Science and Technic Project (No. 2005AA5CG058)
文摘A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distortion method, and their response time and exponential gain coefficient were tested by two-beam coupling experiment. Besides, the effective carrier concentration has been calculated. The results showed that the absorption edges of reduced and oxidized crystals are respectively shifted to violet and Einstein compared with those of the growth state crystal. From oxidation state to growth state to reduction state of the samples, the photo scattering resistance ability and response time decrease while the exponential gain coefficient and concentration of effective carriers increase. The reduction treatment was necessary for the Mg：In：Fe：LiNbO3 crystals to enhance their photorefractive properties.
文摘In 2O 3, MgO and Fe 2O 3 were doped in LiNbO3 and Czochralski method was used to grow In:Mg:Fe:LiNbO 3 crystals. The OH - extension transmission spectra, light scattering resistance ability, two wave coupled diffraction efficiency and response time of the crystal were measured. Codoping In and Mg in crystal will improve its light scattering resistance ability and response time. Doping In can increase the ability to replace antisite Nb and decrease the doping quantity of Mg. All these are propitious to improve the optical homogeneity of crystal. Doping Fe can improve the photorefractive sensitivity for LiNbO 3 crystal. We discussed the site of In, Mg and Fe in LiNbO 3 crystals and the influence of the absorption peak of OH - transmission spectra on photorefractive property for LiNbO 3 crystal.
基金The subject has been supported by Chinese National Advanced Technology 863 Project(Grant No.8632001AA31304)Chinese National 973 Project(Grant No.G19990330).
文摘The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. Compared with As-grown Mg:Mn:Fe:LiNbO 3, the absorption edge in UV-Vis. absorption spectrum of the oxidized sample and the reduced shifts to the violet and the red, respectively. Reduction increases the absorption of crystals in visible light region. In two-wave coupling experiments, the writing time, maximum diffraction efficiency and the erasure time of crystal samples in the same conditions are determined. The results indicate that oxidation and reduction disposing has great effect on the holographic recording properties of these crystals. The reduced crystal exhibits the fastest response time of 160 s among the crystal series. The mechanism of post-disposing effect on the holographic recording properties of Mg:Mn:Fe:LiNbO 3 crystals are investigated.
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.
