Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to ...Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to the optical properties. But heavy ion beam irradiation effects have rarely been studied. The structural, optical, and non-linear optical properties of the doped crystals were analyzed with the characterization studies, such as powder XRD, UV-Visible and second harmonic generation （SHG） measurements, respectively. The results for doped KDP crystal were compared with the results of the pure KDP crystals. The experiment results showed that Li^3＋ irradiation leads to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP were likely to be dissolved and enhance the non-linear optical properties of these materials.展开更多
KDP crystals doped with Chicago Sky Blue 6B（CSB-6B） were grown by traditional lowering temperature method.The optical properties and structural perfection of KDP crystals were investigated by transmittance spectra a...KDP crystals doped with Chicago Sky Blue 6B（CSB-6B） were grown by traditional lowering temperature method.The optical properties and structural perfection of KDP crystals were investigated by transmittance spectra and high-resolution X-ray diffraction,respectively.The results indicate that CSB-6B tends to be incorporated into the pyramidal sector of KDP crystals（PyS-KDP） and lead to inclusions parallel to（101） face.Additionally,the transmittance of as-grown KDP crystals decreases as the amount of CSB-6B increases. Moreover,the rocking curves of PyS-KDP suggest that CSB-6B can deteriorate the structural perfection of PyS-KDP.展开更多
Large-aperture potassium dihydrogen phos- phate （KDP） crystals are widely used in the laser path of inertial confinement fusion （ICF） systems. The most common method of manufacturing half-meter KDP crystals is ult...Large-aperture potassium dihydrogen phos- phate （KDP） crystals are widely used in the laser path of inertial confinement fusion （ICF） systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machin- ing errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.展开更多
To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal,a long-seed KDP crystal with size 471 mm×480 mm×400 mm is rapidly grown.With almost the same high cutting efficiency ...To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal,a long-seed KDP crystal with size 471 mm×480 mm×400 mm is rapidly grown.With almost the same high cutting efficiency to obtain third harmonic generation oriented samples,this long-seed KDP-type crystal can be grown with a shorter seed than that of the cuboid KDP-type crystal.The full width at half maximum of the high-resolution X-ray diffraction of the(200)crystalline face is 28.8 arc seconds,indicating that the long-seed KDP crystal has good crystalline quality.In the wavelength range of 377–1022 nm,the transmittance of the long-seed KDP crystal is higher than 90%.The fluence for the 50%probability of laser-induced damage(LID)is 18.5 J/cm^2(3 ns,355 nm).Several test points survive when the laser fluence exceeds 30 J/cm^2(3 ns,355 nm),indicating the good LID performance of the long-seed KDP crystal.At present,the growth of a long-seed DKDP crystal is under way.展开更多
In order to avoid the defects of mesh distortion when dealing with large deformation problems through using the finite element method, a mess-free simulation method--smooth particle hydrodynamics （SPH） has been intr...In order to avoid the defects of mesh distortion when dealing with large deformation problems through using the finite element method, a mess-free simulation method--smooth particle hydrodynamics （SPH） has been introduced. The material constitutive model of KDP crystal has been established based on the elastic-plastic theory. Then the nano-indentation on the （001） face of KDP crystal has been carried out using SPH method. Simulation results show that the maximum equivalent stress and the maximum plastic strain concentrate on the area that located near the tip of the indenter during the loading process. The distribution shape of Von Mises stress is similar to concentric circles. During the unloading process, no obvious variation of plastic strain distribution exists. The maximum Von Mises stress is mainly located at the indentation and its edge at the end of the unloading process. The approximate direct proportion relationship between the maximum indentation depth and the depth of the maximum Von Mises stress distribution has been discovered when the maximum load is lower than 8 mN. In addition, the nano-indentation experiments on KDP crystal＇s （001） face have been carried out. Both the material parameters and the adjusted stress-strain curve have been verified. The hindering role of the affected layer has been found and analyzed.展开更多
Potassium dihydrogen phosphate(KDP) single crystals are the only nonlinear crystals currently used for electro-optic switches and frequency converters in inertial confinement fusion research, due to their large dimens...Potassium dihydrogen phosphate(KDP) single crystals are the only nonlinear crystals currently used for electro-optic switches and frequency converters in inertial confinement fusion research, due to their large dimension and exclusive physical properties. Based on the traditional solution-growth process, large bulk KDP crystals, usually with sizes up to600 × 600 mm2 so as to make a frequency doubler for the facility requirement loading highly flux of power laser, can be grown in standard Holden-type crystallizers, without spontaneous nucleation and visible defects, one to two orders of magnitude faster than by conventional methods. Pure water and KDP raw material with a few ion impurities such as Fe,Cr, and Al(less than 0.1 ppm) were used. The rapid-growth method includes extreme conditions such as temperature range from 60 to 35℃ , overcooling up to 5℃ , growth rates exceeding 10 mm/day, and crystal size up to 600 mm. The optical parameters of KDP crystals were determined. The optical properties of crystals determined indicate that they are of favorable quality for application in the facility.展开更多
The effects of metaphosphate, boric acid and quaternary ammonium cations with different concentration on the growth habit of KDP crystal are reported. The results are analyzed and discussed, which show that the effect...The effects of metaphosphate, boric acid and quaternary ammonium cations with different concentration on the growth habit of KDP crystal are reported. The results are analyzed and discussed, which show that the effects of different impurities on the growth habit of KDP are not the same. It is due to the different adsorption mechanism of the impurities.展开更多
I. INTRODUCTIONRecently, since high optical quality KDP crystals are required for high energy laser harmonic conversion systems, many studies on KDP crystal are in progress worldwide. There are two main requirements o...I. INTRODUCTIONRecently, since high optical quality KDP crystals are required for high energy laser harmonic conversion systems, many studies on KDP crystal are in progress worldwide. There are two main requirements of the optical property for KDP crys-展开更多
Great interest is being focused on the growth technique of KDP crystal,the first choice material for the fabrication of frequency converter and electro optic switcher used in the studies of inertial confinement fusion...Great interest is being focused on the growth technique of KDP crystal,the first choice material for the fabrication of frequency converter and electro optic switcher used in the studies of inertial confinement fusion (ICF).To reduce the cost of growth,scientists are endeavoring to promote the growth rate.The“point seed” method is one of rapid growth techniques recently developed by Lawrence Livermore National Laboratory.In the former technique,crystals are grown in all three directions at an averaged rate of 10 15mm/day. Impurities are regarded as one of the factors to inhibit the growth rate.It is generally accepted that high valence cationic ions,such as Fe 3+ ,Cr 3+ ,Al 3+ ,etc,are easy to be adsorbed on the prismatic faces and inhibit their growth.Some anions,especially those have ability to form strong hydra bond,such as phosphate derivatives (polyphosphate,metaphosphate,pyrophosphate,etc) have significant inhibiting effects on the growth of KDP pyramidal face.It is suggested that the H bonding is the key interaction force between the growing surface and the impurities.展开更多
文摘Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to the optical properties. But heavy ion beam irradiation effects have rarely been studied. The structural, optical, and non-linear optical properties of the doped crystals were analyzed with the characterization studies, such as powder XRD, UV-Visible and second harmonic generation （SHG） measurements, respectively. The results for doped KDP crystal were compared with the results of the pure KDP crystals. The experiment results showed that Li^3＋ irradiation leads to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP were likely to be dissolved and enhance the non-linear optical properties of these materials.
基金Supported by the State High Technology Program for Inertial Confinement Fusion and National Natural Science Foundation of China (No 59823003, 50721002)China Postdoctoral Science Foundation (No 20080441139)Youth Scientist Fund of Shandong Province (No 2004BS04022)
文摘KDP crystals doped with Chicago Sky Blue 6B（CSB-6B） were grown by traditional lowering temperature method.The optical properties and structural perfection of KDP crystals were investigated by transmittance spectra and high-resolution X-ray diffraction,respectively.The results indicate that CSB-6B tends to be incorporated into the pyramidal sector of KDP crystals（PyS-KDP） and lead to inclusions parallel to（101） face.Additionally,the transmittance of as-grown KDP crystals decreases as the amount of CSB-6B increases. Moreover,the rocking curves of PyS-KDP suggest that CSB-6B can deteriorate the structural perfection of PyS-KDP.
文摘Large-aperture potassium dihydrogen phos- phate （KDP） crystals are widely used in the laser path of inertial confinement fusion （ICF） systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machin- ing errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.
基金supported by the National Natural Science Foundation of China(No.11535010)。
文摘To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal,a long-seed KDP crystal with size 471 mm×480 mm×400 mm is rapidly grown.With almost the same high cutting efficiency to obtain third harmonic generation oriented samples,this long-seed KDP-type crystal can be grown with a shorter seed than that of the cuboid KDP-type crystal.The full width at half maximum of the high-resolution X-ray diffraction of the(200)crystalline face is 28.8 arc seconds,indicating that the long-seed KDP crystal has good crystalline quality.In the wavelength range of 377–1022 nm,the transmittance of the long-seed KDP crystal is higher than 90%.The fluence for the 50%probability of laser-induced damage(LID)is 18.5 J/cm^2(3 ns,355 nm).Several test points survive when the laser fluence exceeds 30 J/cm^2(3 ns,355 nm),indicating the good LID performance of the long-seed KDP crystal.At present,the growth of a long-seed DKDP crystal is under way.
基金supported by the National Basic Research Program of China(No.51135002)the Science Fund for Creative Research Groups(No.51321004)
文摘In order to avoid the defects of mesh distortion when dealing with large deformation problems through using the finite element method, a mess-free simulation method--smooth particle hydrodynamics （SPH） has been introduced. The material constitutive model of KDP crystal has been established based on the elastic-plastic theory. Then the nano-indentation on the （001） face of KDP crystal has been carried out using SPH method. Simulation results show that the maximum equivalent stress and the maximum plastic strain concentrate on the area that located near the tip of the indenter during the loading process. The distribution shape of Von Mises stress is similar to concentric circles. During the unloading process, no obvious variation of plastic strain distribution exists. The maximum Von Mises stress is mainly located at the indentation and its edge at the end of the unloading process. The approximate direct proportion relationship between the maximum indentation depth and the depth of the maximum Von Mises stress distribution has been discovered when the maximum load is lower than 8 mN. In addition, the nano-indentation experiments on KDP crystal＇s （001） face have been carried out. Both the material parameters and the adjusted stress-strain curve have been verified. The hindering role of the affected layer has been found and analyzed.
文摘Potassium dihydrogen phosphate(KDP) single crystals are the only nonlinear crystals currently used for electro-optic switches and frequency converters in inertial confinement fusion research, due to their large dimension and exclusive physical properties. Based on the traditional solution-growth process, large bulk KDP crystals, usually with sizes up to600 × 600 mm2 so as to make a frequency doubler for the facility requirement loading highly flux of power laser, can be grown in standard Holden-type crystallizers, without spontaneous nucleation and visible defects, one to two orders of magnitude faster than by conventional methods. Pure water and KDP raw material with a few ion impurities such as Fe,Cr, and Al(less than 0.1 ppm) were used. The rapid-growth method includes extreme conditions such as temperature range from 60 to 35℃ , overcooling up to 5℃ , growth rates exceeding 10 mm/day, and crystal size up to 600 mm. The optical parameters of KDP crystals were determined. The optical properties of crystals determined indicate that they are of favorable quality for application in the facility.
基金This work was supported by the State High Technology Program for Inertial Confinement Fusion and the National Natural Science Foundation of China (Grant No. 59823003).
文摘The effects of metaphosphate, boric acid and quaternary ammonium cations with different concentration on the growth habit of KDP crystal are reported. The results are analyzed and discussed, which show that the effects of different impurities on the growth habit of KDP are not the same. It is due to the different adsorption mechanism of the impurities.
文摘I. INTRODUCTIONRecently, since high optical quality KDP crystals are required for high energy laser harmonic conversion systems, many studies on KDP crystal are in progress worldwide. There are two main requirements of the optical property for KDP crys-
文摘Great interest is being focused on the growth technique of KDP crystal,the first choice material for the fabrication of frequency converter and electro optic switcher used in the studies of inertial confinement fusion (ICF).To reduce the cost of growth,scientists are endeavoring to promote the growth rate.The“point seed” method is one of rapid growth techniques recently developed by Lawrence Livermore National Laboratory.In the former technique,crystals are grown in all three directions at an averaged rate of 10 15mm/day. Impurities are regarded as one of the factors to inhibit the growth rate.It is generally accepted that high valence cationic ions,such as Fe 3+ ,Cr 3+ ,Al 3+ ,etc,are easy to be adsorbed on the prismatic faces and inhibit their growth.Some anions,especially those have ability to form strong hydra bond,such as phosphate derivatives (polyphosphate,metaphosphate,pyrophosphate,etc) have significant inhibiting effects on the growth of KDP pyramidal face.It is suggested that the H bonding is the key interaction force between the growing surface and the impurities.
