The EPR parameters of trivalent Er（3＋） ions doped in hexagonal Ga N crystal have been studied by diagonalizing the 364×364 complete energy matrices. The results indicate that the resonance ground states may be...The EPR parameters of trivalent Er（3＋） ions doped in hexagonal Ga N crystal have been studied by diagonalizing the 364×364 complete energy matrices. The results indicate that the resonance ground states may be derived from the Kramers doublet Γ6. The EPR g-factors may be ascribed to the stronger covalent bonding and nephelauxetic effects compared with other rare-earth doped complexes, as a result of the mismatch of ionic radii of the impurity Er（3＋）ion and the replaced Ga（3＋） ion apart from the intrinsic covalency of host Ga N. Furthermore, the J–J mixing effects on the EPR parameters from the high-lying manifolds have been evaluated. It is found that the dominant J–J mixing contribution is from the manifold 2K（15/2）, which accounts for about 2.5%. The next important J–J contribution arises from the crystal–field mixture between the ground state 4I（15/2） and the first excited state4I（13/2）, and is usually less than 0.2%. The contributions from the rest states may be ignored.展开更多
研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激...研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激励强度增大时 ,系统的响应可从一个极限环变为一个扩散的极限环 ;在一定的条件下 ,系统可有两个稳定的稳态解及随机跳跃现象。展开更多
The polarized absorption spectra of Tm3+/Er3+:YVO4 crystal were measured at room temperature. Based on the Judd-Ofelt theory, the spectral parameters were obtained: the intensity parameters Wl of Tm3+ in Tm/Er:YVO4 cr...The polarized absorption spectra of Tm3+/Er3+:YVO4 crystal were measured at room temperature. Based on the Judd-Ofelt theory, the spectral parameters were obtained: the intensity parameters Wl of Tm3+ in Tm/Er:YVO4 crystal: W2 = 10.69×10-20, W4 = 0.604×10-20, W6 = 2.05×10-20 cm2 for the (100) face and W2 = 10.43×10-20, W4 = 0.13×10-20, W6 = 1.83×10-20 cm2 for the (001) face. Based on these values, the oscillator strength, radioactive lifetime and fluorescence branch ratio were calculated for Tm3+ in Tm/Er:YVO4 crystal.展开更多
Er^(3+)-doped Gd_2O_3 -SiO_2 -B_2O_3 -Na_2O glasses were prepared, and formation range of glass of Gd_2O_3 -SiO_2 -B_2O_3 system was experimentally obtained. It is found that the glass phase can be formed only when th...Er^(3+)-doped Gd_2O_3 -SiO_2 -B_2O_3 -Na_2O glasses were prepared, and formation range of glass of Gd_2O_3 -SiO_2 -B_2O_3 system was experimentally obtained. It is found that the glass phase can be formed only when the content of SiO_2 is 0～50%(molar fraction), Gd_2O_3 is 0～30%(molar fraction) and B_2O_3 is above 20%(molar fraction) in this glass system. The glass can also be obtained but becomes translucent at the contents of 60%(molar fraction) SiO_2 and 30% Gd_2O_3 , or at the contents of 60%(molar fraction) SiO_2 and 30%(molar fraction) B_2O_3. There is no glass phase formed in other glass components. Glass forming ability for Gd_2O_3 content of 10%, was characterized by the value of β, the parameter of crystallization tendency, which is 0.32～1.76, obtained from the differential thermal analysis. The absorption and emission cross section, the J-O parameters Ωt_((2,4,6)) and radiative transition probabilities were calculated by using the theory of McCumber and Judd-Ofelt. The emission properties at 1.5 μm of the samples are discussed with the product of full width at half maximum and stimulated emission cross section. It can be seen that the value of the FWHM×σ_e^(peak) product in the prepared glass is more than those of germanate, silicate and phosphate glasses. Furthermore, the maximum value of the product among these glasses reported in this work is close to that of oxyfluoride silicate glass. Therefore, the Er^(3+)-doped gadolinium borosilicate glass in this paper is a candidate for broadband erbium doped fiber amplifiers.展开更多
基金Project supported by the Foundation of Education Department of Shaanxi Province,China(Grant No.16JK1402)
文摘The EPR parameters of trivalent Er（3＋） ions doped in hexagonal Ga N crystal have been studied by diagonalizing the 364×364 complete energy matrices. The results indicate that the resonance ground states may be derived from the Kramers doublet Γ6. The EPR g-factors may be ascribed to the stronger covalent bonding and nephelauxetic effects compared with other rare-earth doped complexes, as a result of the mismatch of ionic radii of the impurity Er（3＋）ion and the replaced Ga（3＋） ion apart from the intrinsic covalency of host Ga N. Furthermore, the J–J mixing effects on the EPR parameters from the high-lying manifolds have been evaluated. It is found that the dominant J–J mixing contribution is from the manifold 2K（15/2）, which accounts for about 2.5%. The next important J–J contribution arises from the crystal–field mixture between the ground state 4I（15/2） and the first excited state4I（13/2）, and is usually less than 0.2%. The contributions from the rest states may be ignored.
文摘研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激励强度增大时 ,系统的响应可从一个极限环变为一个扩散的极限环 ;在一定的条件下 ,系统可有两个稳定的稳态解及随机跳跃现象。
文摘The polarized absorption spectra of Tm3+/Er3+:YVO4 crystal were measured at room temperature. Based on the Judd-Ofelt theory, the spectral parameters were obtained: the intensity parameters Wl of Tm3+ in Tm/Er:YVO4 crystal: W2 = 10.69×10-20, W4 = 0.604×10-20, W6 = 2.05×10-20 cm2 for the (100) face and W2 = 10.43×10-20, W4 = 0.13×10-20, W6 = 1.83×10-20 cm2 for the (001) face. Based on these values, the oscillator strength, radioactive lifetime and fluorescence branch ratio were calculated for Tm3+ in Tm/Er:YVO4 crystal.
文摘Er^(3+)-doped Gd_2O_3 -SiO_2 -B_2O_3 -Na_2O glasses were prepared, and formation range of glass of Gd_2O_3 -SiO_2 -B_2O_3 system was experimentally obtained. It is found that the glass phase can be formed only when the content of SiO_2 is 0～50%(molar fraction), Gd_2O_3 is 0～30%(molar fraction) and B_2O_3 is above 20%(molar fraction) in this glass system. The glass can also be obtained but becomes translucent at the contents of 60%(molar fraction) SiO_2 and 30% Gd_2O_3 , or at the contents of 60%(molar fraction) SiO_2 and 30%(molar fraction) B_2O_3. There is no glass phase formed in other glass components. Glass forming ability for Gd_2O_3 content of 10%, was characterized by the value of β, the parameter of crystallization tendency, which is 0.32～1.76, obtained from the differential thermal analysis. The absorption and emission cross section, the J-O parameters Ωt_((2,4,6)) and radiative transition probabilities were calculated by using the theory of McCumber and Judd-Ofelt. The emission properties at 1.5 μm of the samples are discussed with the product of full width at half maximum and stimulated emission cross section. It can be seen that the value of the FWHM×σ_e^(peak) product in the prepared glass is more than those of germanate, silicate and phosphate glasses. Furthermore, the maximum value of the product among these glasses reported in this work is close to that of oxyfluoride silicate glass. Therefore, the Er^(3+)-doped gadolinium borosilicate glass in this paper is a candidate for broadband erbium doped fiber amplifiers.
