Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/008
Ma Xing-Kun, Chen Hong, He Yuan-jin, Y. Nagashima, H. Saito, T. Hyodo
Positron lifetime spectra have been measured in two kinds of carbon nanotube powders as a function of temperature range between 32 and 296 K. It has been found that all spectra are essentially temperature-independent in the above temperature range. The results of analysis show that there are three components in the powders of carbon nanotube with an average diameter of 30 nm, and four components in the powders of carbon nanotube with typical diameters of around 15 nm. The average values of lifetime components obtained at various temperatures are about 220, 390 ps, and 2.0 ns for the former, and about 140, 300, 650 ps and 6.4 ns for the latter.
{"title":"Positron annihilation in carbon nanotube powders","authors":"Ma Xing-Kun, Chen Hong, He Yuan-jin, Y. Nagashima, H. Saito, T. Hyodo","doi":"10.1088/1004-423X/8/10/008","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/008","url":null,"abstract":"Positron lifetime spectra have been measured in two kinds of carbon nanotube powders as a function of temperature range between 32 and 296 K. It has been found that all spectra are essentially temperature-independent in the above temperature range. The results of analysis show that there are three components in the powders of carbon nanotube with an average diameter of 30 nm, and four components in the powders of carbon nanotube with typical diameters of around 15 nm. The average values of lifetime components obtained at various temperatures are about 220, 390 ps, and 2.0 ns for the former, and about 140, 300, 650 ps and 6.4 ns for the latter.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134265949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/005
G. M. A. Al-Kader
Much attention is given for the squeezed coherent states (SCS's) superposition. The s-parameterized charactristic function (CF) for the output field with the superposition of SCS's as input field is given. The s-parameterized quasiprobability distribution function (QDF) for the output field with superposition of SCS's as input state are investigated. Various moments are calculated by using the s-parameterized CF for that field. The Glauber second-order coherence function is calculated. The quadrature squeezing for the output field are discussed. Some QDF's of the output fields are plotted as functions of the interaction time. Phase properties of the superpostion of SCS's are studied. The s-parameterized phase distributions obtained by integrating the s-parameterized QDF over radial variable are illustrated.
{"title":"Linear amplifier via the squeezed coherent states superpositions","authors":"G. M. A. Al-Kader","doi":"10.1088/1004-423X/8/10/005","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/005","url":null,"abstract":"Much attention is given for the squeezed coherent states (SCS's) superposition. The s-parameterized charactristic function (CF) for the output field with the superposition of SCS's as input field is given. The s-parameterized quasiprobability distribution function (QDF) for the output field with superposition of SCS's as input state are investigated. Various moments are calculated by using the s-parameterized CF for that field. The Glauber second-order coherence function is calculated. The quadrature squeezing for the output field are discussed. Some QDF's of the output fields are plotted as functions of the interaction time. Phase properties of the superpostion of SCS's are studied. The s-parameterized phase distributions obtained by integrating the s-parameterized QDF over radial variable are illustrated.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134055756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/006
Jian-lun Yang, Gen-xing Wang, Qi-hua Zhu, Shu-huai Wen, Zhong-li Liu, Hong-qiong Yang, Z. Tang, Shi-bin Wu, W. Fan
We have designed a fast, sensitive neutron detector for recording the fusion history of inertial confinement fusion experiments. With a response time of < 40 ps, it was for burn history measurements for deuterium/tritium-filled targets producing as few as similar 108 neutrons/shot. The detector is based on the fast rise-time (< 20 ps) of BC422 plastic scintillator which, shaped in thin cylinder sheet or curved (in a geometry compensating way) plate, acts as a neutron-to-light converter in a Pb shielding. The Pb shielding shields the scintillator from target x-ray, scattered light and target debris and allows the scintillator to be positioned within 3 cm from the target. The scintillator emits light with wavelengths from 350 to 450 nm. A group of achromatic lens relays the scintillator image along a 1 m optical path to the S20 photocathode of a streak camera outside the chamber. Lens coupling was chosen to give acceptable temporal dispersion. In the design phase, a computer code was programmed to calculate and improve the physical parameters of the optical system, such as light collection efficiency, time dispersion, image position, intensity distribution on the image plane, etc. Some of these parameters were finally measured using a deuterium lamp and a piece of BC422 scintillator activated by x-ray or 0.35 μm laser pulse. The measured results agree well with the prediction of the computer code.
{"title":"Neutron detector for fusion burn history measurements","authors":"Jian-lun Yang, Gen-xing Wang, Qi-hua Zhu, Shu-huai Wen, Zhong-li Liu, Hong-qiong Yang, Z. Tang, Shi-bin Wu, W. Fan","doi":"10.1088/1004-423X/8/10/006","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/006","url":null,"abstract":"We have designed a fast, sensitive neutron detector for recording the fusion history of inertial confinement fusion experiments. With a response time of < 40 ps, it was for burn history measurements for deuterium/tritium-filled targets producing as few as similar 108 neutrons/shot. The detector is based on the fast rise-time (< 20 ps) of BC422 plastic scintillator which, shaped in thin cylinder sheet or curved (in a geometry compensating way) plate, acts as a neutron-to-light converter in a Pb shielding. The Pb shielding shields the scintillator from target x-ray, scattered light and target debris and allows the scintillator to be positioned within 3 cm from the target. The scintillator emits light with wavelengths from 350 to 450 nm. A group of achromatic lens relays the scintillator image along a 1 m optical path to the S20 photocathode of a streak camera outside the chamber. Lens coupling was chosen to give acceptable temporal dispersion. In the design phase, a computer code was programmed to calculate and improve the physical parameters of the optical system, such as light collection efficiency, time dispersion, image position, intensity distribution on the image plane, etc. Some of these parameters were finally measured using a deuterium lamp and a piece of BC422 scintillator activated by x-ray or 0.35 μm laser pulse. The measured results agree well with the prediction of the computer code.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"475 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123475848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/004
Long De-shun, Xu Hui-zhong, Wang Yan-sen, Zhao Guo-qing, Peng Shuming, Zhao Peng-ji, Xu Zhi-lei
The diffusion barriers for the single helium atom in 3d transition metals are systematically studied by effective medium theory without any adjustable parameters. In the calculation, the relaxiation effects of lattice are taken into account. The comparison of our calculated results with the available experimental data and other theoretical values shows good agreement.
{"title":"CALCULATION OF DIFFUSION BARRIERS FOR HELIUM ATOM IN METALS","authors":"Long De-shun, Xu Hui-zhong, Wang Yan-sen, Zhao Guo-qing, Peng Shuming, Zhao Peng-ji, Xu Zhi-lei","doi":"10.1088/1004-423X/8/10/004","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/004","url":null,"abstract":"The diffusion barriers for the single helium atom in 3d transition metals are systematically studied by effective medium theory without any adjustable parameters. In the calculation, the relaxiation effects of lattice are taken into account. The comparison of our calculated results with the available experimental data and other theoretical values shows good agreement.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127605099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/001
Jiu-ren Zheng
In this paper, first of all, we proved if the ideal Bose gas with a finite volume and number of particles has a non-degenerate single-particle energy level n, the chemical potential μ can take the value μn = n and there is a phase transition temperature Tp,n, where n = 0,1,2 Taking 0 ≤ n Tp,n+1. When the temperature T > Tp,n or T ≤ Tp,n+1, μ # n and the most probable occupation number Nn = 0. In the temperature interval Tp,n ≥ T > Tp,n+1, μ = n and 0 ≤ Nn = N - NjsupNn, where Nj is the most probable occupation number in the degenerate level j. Thus, if the finite ideal Bose gas has some non-degenerate single-particle levels, there exists a characteristic temperature Tp = Tp,0. The chemical potential μ is quantized when T ≤ Tp, and this leads to the creation of a macroscopic quantum state (pure state) or Bose-Einstein condensation phase. Tp = Tp,0 is a first-order phase transition point, Tp,n#0 is a zero-order phase transition point. Next, we obtained a new expression of the most probable distribution of the finite ideal Bose gas. In this expression Nj is directly proportional to gj - 1, where gj and Nj are, respectively, the degeneracy and the most probable occupation number in the degenerate level j. This property agrees with what chemical potential can be quantized if there is a non-degenerate level for the finite ideal Bose gas. Finally, using this expression, we defined a micro-partition function M, obtained the statistical expressions of some thermodynamical quantities.
{"title":"CHEMICAL POTENTIAL QUANTIZATION AND BOSE-EINSTEIN CONDENSATION","authors":"Jiu-ren Zheng","doi":"10.1088/1004-423X/8/10/001","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/001","url":null,"abstract":"In this paper, first of all, we proved if the ideal Bose gas with a finite volume and number of particles has a non-degenerate single-particle energy level n, the chemical potential μ can take the value μn = n and there is a phase transition temperature Tp,n, where n = 0,1,2 Taking 0 ≤ n Tp,n+1. When the temperature T > Tp,n or T ≤ Tp,n+1, μ # n and the most probable occupation number Nn = 0. In the temperature interval Tp,n ≥ T > Tp,n+1, μ = n and 0 ≤ Nn = N - NjsupNn, where Nj is the most probable occupation number in the degenerate level j. Thus, if the finite ideal Bose gas has some non-degenerate single-particle levels, there exists a characteristic temperature Tp = Tp,0. The chemical potential μ is quantized when T ≤ Tp, and this leads to the creation of a macroscopic quantum state (pure state) or Bose-Einstein condensation phase. Tp = Tp,0 is a first-order phase transition point, Tp,n#0 is a zero-order phase transition point. Next, we obtained a new expression of the most probable distribution of the finite ideal Bose gas. In this expression Nj is directly proportional to gj - 1, where gj and Nj are, respectively, the degeneracy and the most probable occupation number in the degenerate level j. This property agrees with what chemical potential can be quantized if there is a non-degenerate level for the finite ideal Bose gas. Finally, using this expression, we defined a micro-partition function M, obtained the statistical expressions of some thermodynamical quantities.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123911688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/007
Shi Yun-long, Zhang Yu-mei, Chen Hong, Wu Xiang
The ground state and elementary excitations of the Peierls-Hubbard model are studied by using Gaussian wave functional method. The results show that the charge and spin degrees of freedom couple to each other due to the simultaneous existance of the dimerization and Hubbard repulsions. In the region of βs2 > 2π the spin gap ms is still present. Also the influence of Hubbard repulsions on the dimerization is derived from the critical behavior of ground state energy.
{"title":"Ground state and elementary excitations of the Peierls-Hubbard model","authors":"Shi Yun-long, Zhang Yu-mei, Chen Hong, Wu Xiang","doi":"10.1088/1004-423X/8/10/007","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/007","url":null,"abstract":"The ground state and elementary excitations of the Peierls-Hubbard model are studied by using Gaussian wave functional method. The results show that the charge and spin degrees of freedom couple to each other due to the simultaneous existance of the dimerization and Hubbard repulsions. In the region of βs2 > 2π the spin gap ms is still present. Also the influence of Hubbard repulsions on the dimerization is derived from the critical behavior of ground state energy.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125692719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1088/1004-423X/8/10/003
Zhang Jing-Tao, C. Zhaoyang, Xu Zhizhan
Dynamics of a two-level atom moving in an electromagnetic field is studied. The atomic motion gives rise to a momentum-dependent detuning which holds back the atomic transition, and leads to a momentum-dependent Rabi oscillation which causes an overlapping among different Rabi oscillations. When the field is in a Fock state, the atomic population and the mean momentum of the atom exhibit damping oscillation, the damping rate is related to the momentum distribution; the collapse-revival phenomena of the atomic population and the mean momentum will occur if the atomic momentum has some special distribution. When the field is in a superposition state, the collapse-revival phenomena are modified by the atomic momentum distribution and disappear for the wider atomic momentum wavepackets. We also find that each atomic level will split into two sublevels with the same energy difference when the field is in a Fock state and the atom has a definite momentum.
{"title":"Interaction between a moving atom and an electromagnetic wave","authors":"Zhang Jing-Tao, C. Zhaoyang, Xu Zhizhan","doi":"10.1088/1004-423X/8/10/003","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/003","url":null,"abstract":"Dynamics of a two-level atom moving in an electromagnetic field is studied. The atomic motion gives rise to a momentum-dependent detuning which holds back the atomic transition, and leads to a momentum-dependent Rabi oscillation which causes an overlapping among different Rabi oscillations. When the field is in a Fock state, the atomic population and the mean momentum of the atom exhibit damping oscillation, the damping rate is related to the momentum distribution; the collapse-revival phenomena of the atomic population and the mean momentum will occur if the atomic momentum has some special distribution. When the field is in a superposition state, the collapse-revival phenomena are modified by the atomic momentum distribution and disappear for the wider atomic momentum wavepackets. We also find that each atomic level will split into two sublevels with the same energy difference when the field is in a Fock state and the atom has a definite momentum.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"35 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116647991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-09-20DOI: 10.1088/1004-423X/8/9/006
Lü Rui-bo, X. Ke-shu, Zhang Shu-yan, Gu Xiang, Xing Zhong-jing, Deng Huihua, Gu Jianhua, Xiao Zhong-dang, L. Zuhong
The stripe-shaped domain (SSD) structure was prepared in the initial ferroelectric liquid crystal (FLC) alignment without the application of an external electric field, which was realized by the aligning layer modification through the doping of tin tetra-2, 4-dimethyl phenoxy phthalocyanine (SnPc) into the rubbed polyimide films. Atomic force microscopy was used to investigate the alignment films and the corresponding aligning ability was evaluated through the pre-tilt angle measurement. The memory capability and the contrast ratio of thus aligned SSFLC cells have been enhanced and improved with the appearance of the SSD structure. The electrically controlled 64 × 64 FLC spatial light modulator was fabricated using the improved aligning method, which proves valuable for the practical device fabrication.
{"title":"Preparation of stripe-shaped domain structure in ferroelectric liquid crystal and the fabrication of spatial light modulator","authors":"Lü Rui-bo, X. Ke-shu, Zhang Shu-yan, Gu Xiang, Xing Zhong-jing, Deng Huihua, Gu Jianhua, Xiao Zhong-dang, L. Zuhong","doi":"10.1088/1004-423X/8/9/006","DOIUrl":"https://doi.org/10.1088/1004-423X/8/9/006","url":null,"abstract":"The stripe-shaped domain (SSD) structure was prepared in the initial ferroelectric liquid crystal (FLC) alignment without the application of an external electric field, which was realized by the aligning layer modification through the doping of tin tetra-2, 4-dimethyl phenoxy phthalocyanine (SnPc) into the rubbed polyimide films. Atomic force microscopy was used to investigate the alignment films and the corresponding aligning ability was evaluated through the pre-tilt angle measurement. The memory capability and the contrast ratio of thus aligned SSFLC cells have been enhanced and improved with the appearance of the SSD structure. The electrically controlled 64 × 64 FLC spatial light modulator was fabricated using the improved aligning method, which proves valuable for the practical device fabrication.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129789186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-09-20DOI: 10.1088/1004-423X/8/9/004
Zhang Jing-Tao, C. Zhaoyang, Xu Zhi-zhan
In this paper we investigate the distance between density operators in multiphoton processes. We study the distances between the time-evolved states of the atom, of the field, and of the total system and their respective reference states, compare them with the atomic inversion as well as the purity of the field, disclose their corresponding relations in various multiphoton processes. The physical interpretations are given by using a fully quantized Bloch equation in the two-photon process.
{"title":"Distance between density operators in multiphoton processes","authors":"Zhang Jing-Tao, C. Zhaoyang, Xu Zhi-zhan","doi":"10.1088/1004-423X/8/9/004","DOIUrl":"https://doi.org/10.1088/1004-423X/8/9/004","url":null,"abstract":"In this paper we investigate the distance between density operators in multiphoton processes. We study the distances between the time-evolved states of the atom, of the field, and of the total system and their respective reference states, compare them with the atomic inversion as well as the purity of the field, disclose their corresponding relations in various multiphoton processes. The physical interpretations are given by using a fully quantized Bloch equation in the two-photon process.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132352604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-09-01DOI: 10.1088/1004-423X/8/9/005
Chi Ming-jun, Dou Shuo-xing, Ye Pei-xian
Intensity dependence of the total effective trap density Neff is studied theoretically for the two-centre and the three-charge-state photorefractive crystals. The results show that Neff always increases with increasing intensity in three-charge-state crystals, whereas it has more complicated behaviors in two-centre crystals. When SDγT/STγD is small, Neff increases and tends to saturate with increasing intensity for both type-A and type-B two-centre crystals. When SDγT/STγD is large, Neff increases to a maximum and then decreases a little for type-A crystals and decreases greatly for type-B crystals. The different intensity dependences of Neff in the two types of crystals come from their different level structures.
从理论上研究了双中心和三电荷态光折变晶体的总有效阱密度Neff的强度依赖性。结果表明，在三电荷态晶体中，Neff总是随着强度的增加而增加，而在双中心晶体中，Neff的行为更为复杂。当sd - γ t / st - γ d较小时，a型和b型双中心晶体的Neff均随强度的增加而增大并趋于饱和。当sd - γ t / st - γ d较大时，a型晶体Neff增大到最大值后减小，b型晶体Neff减小较大。两种晶体的内夫强度依赖性的不同来自于它们不同的能级结构。
{"title":"Theoretical study of the intensity dependence of total effective trap density in photorefractive crystals","authors":"Chi Ming-jun, Dou Shuo-xing, Ye Pei-xian","doi":"10.1088/1004-423X/8/9/005","DOIUrl":"https://doi.org/10.1088/1004-423X/8/9/005","url":null,"abstract":"Intensity dependence of the total effective trap density Neff is studied theoretically for the two-centre and the three-charge-state photorefractive crystals. The results show that Neff always increases with increasing intensity in three-charge-state crystals, whereas it has more complicated behaviors in two-centre crystals. When SDγT/STγD is small, Neff increases and tends to saturate with increasing intensity for both type-A and type-B two-centre crystals. When SDγT/STγD is large, Neff increases to a maximum and then decreases a little for type-A crystals and decreases greatly for type-B crystals. The different intensity dependences of Neff in the two types of crystals come from their different level structures.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123930077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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