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
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
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.
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.
