Temperature dependence of the 1.064-mu m stimulated emission cross-section of Cr : Nd : YAG crystal

The fluorescence emission spectra of Cr:Nd:YAG crystal are measured and the effective stimulated emission cross-section of the crystal is obtained from -80 to +80 degrees C. A linear temperature dependence between -80 and +80 degrees C is reported for the 1.064-mu m peak stimulated emission cross-section of Cr:Nd:YAG crystal. (C) 2005 Elsevier Ltd. All rights reserved.

Cr,Yb:YAG晶体的自调Q激光性能

用光纤耦合激光二极管抽运Cr,Yb:YAG晶体获得了1.03 μm的自调Q激光输出,输出的调Q脉冲非常稳定,抽运阈值功率为680 mW,脉冲宽度为3.3 ns,获得的平均功率为156 mW,斜率效率为18.5%。随着抽运功率的增大,重复频率成线性增长,而脉宽略有减少,单脉冲能量和峰值功率都始终呈增大趋势。光束质量因子M2为1.17。

铬、钕双掺钆镓石榴石（Cr^4＋，Nd^3＋）：Gd3Ga5O12激光晶体光学性能的研究

用提拉法生长了掺铬、钕的钆镓石榴石(Cr^4+，Nd^3+：GGG)自调Q激光品体。报道了室温下的吸收光谱和荧光光谱特性。分析了Cr离子浓度对光谱性质的影响。比较了Cr^4+：GGG，Nd^3+：GGG和(Cr^4+，Nd^3+)：GGG晶体吸收光谱的关系。测量了(Cr^4+，Nd^3+)：GGG晶体和Nd^3+：GGG晶体的荧光寿命，它们分别是33μs和250μs。实验表明，(Cr^4+，Nd^3+)：GGG晶体是一种非常有潜力的自调Q激光晶体，可以实现大功率激光器的小型化和全固态化。

Cr^4＋，Nd3＋共掺的钆镓石榴石（Cr，Nd：GGG）的光谱性能与光谱参数的研究

用提拉法生长了掺铬、钕的钆镓石榴石(Cr^4+，Nd^3+:GGG)晶体，研究了室温下的吸收光谱和荧光光谱性质，以及晶体中Cr离子浓度对Nd离子光谱性质的影响。应用Judd—ofelt理论计算了强度参数Ωt(t=2，4，6)，自发辐射跃迁几率、荧光分支比和辐射辱命等光谱参数。应用McCumber理论计算^4F3/2→^4I11/2能级跃迁的受激发射截面。结果表明：Cr^3+在300～900nm之间较强地增加了吸收截面，尤其是伴随Cr^3+→Nd^3+有效的能量转移。Cr^4+在1．06μm附近的吸收减弱了

氧化铝透明陶瓷中Cr3+的发光性能

采用传统无压烧结工艺制备出透明性良好的掺Cr3+氧化铝陶瓷;测定了陶瓷的吸收光谱、发射光谱和激发光谱。结果表明,氧化铝陶瓷吸收峰与红宝石单晶一致,吸收截面大小与单晶相近;陶瓷中Cr3+离子所处格位的晶体场强较单晶弱,但其发射谱仍有较好的锐线发射;陶瓷中微量添加剂以及晶界的存在使得Al2O3晶胞发生畸变,造成其发射峰宽化。

Yb：YAG及Cr，Yb：YAG晶体的发光特性

研究了室温下Yb：YAG的上转换荧光光谱，此荧光归因于Yb^3＋离子的“合作”发光和Yb抖离子到稀土杂质离子的能量转移。测试了Yb；YAG晶体的X射线荧光，发光峰对应于电荷迁移态到Yb^3＋离子的基态、激光态间的跃迁。研究了Cr，Yb：YAG晶体的荧光光谱。讨论了Cr^4＋激光输出的可能性。

Cr^4＋在Al2O3透明陶瓷中的发光行为

采用传统无压烧结工艺制备出透明性良好的掺Cr的Al2O3透明陶瓷；测定了其吸收光谱和荧光光谱，发现在Al2O3六配位的八面体结构中，除了有Cr^3＋离子的特征吸收峰外，由于有Mg^2＋的电荷补偿作用，也有Cr^4＋离子，Cr^4＋的荧光发射峰位于1223nm附近，与Cr^4＋在四面体中的发光行为一致。但其荧光发射峰较窄，半高宽△λ仅为37nm。

Growth of high quality Cr, Yb codoped gadolinium gallium garnet (Gd3Ga5O12) crystal and its spectral properties

The Cr(0.1%),Yb(10%):GGG crystals have been grown by the Czochralski method. The chemical composition is: Yb0.33Gd2.47Cr0.005Ga5.2O12. There are no observed Yb3+ ions substituting Ga3+ ions, just like that of Yb:GGG crystals. The defects in Cr,Yb:GGG crystal were also investigated. The absorption and emission spectra of Cr,Yb:GGG crystal at room temperature have been measured. The 02 and H-2 annealing effect of Cr,Yb:GGG crystal have been compared. Cr3+ can greatly weak the visible luminescence of this crystal. The Cr-Yb-codoped crystals may be potential materials for compact, efficient, high stability LD pumped solid state lasers. (C) 2006 Elsevier B.V. All rights reserved.

Single crystal beta-Ga2O3: Cr grown by floating zone technique and its optical properties

beta-Ga2O3: Cr single crystals were grown by floating zone technique. Absorption spectra and fluorescence spectra were measured at room temperature. The values of field splitting parameter Dq and Racah parameter B were obtained by the peak values of absorption spectra. The value 10Dq/B=23.14 manifests that in beta-Ga2O3 crystals Cr3+ ions are influenced by low energy crystal field. After high temperature annealing in air, the Cr3+ intrinsic emission was enhanced and the green luminescence disappeared. The strong and broad 691 nm emission was obtained at 420 nm excitation due to the electron transition occurred from T-4(2) to (4)A(2). The studies manifest that the beta-Ga2O3 crystals have the potential application for tunable laser.

β-Ga2O3：Cr单晶体的浮区法生长及光学特性

利用浮区法生长得到β-Ga2O3：Cr单晶体．在室温下测试了β-Ga2O3：Cr单晶体的吸收光谱和发射光谱．通过吸收光谱计算了晶体场分裂系数Dq和Racah系数，得到10Dq/B=23．14，表明Cr^3＋在β-Ga2O3晶体中处于较弱的晶体场β-Ga2O3：Cr单晶体经高温退火后Cr^3＋的发射明显加强，而绿光的发射减弱．采用420nm波长激发，在691nm可得到强而宽的特征发射，此发射对应于Cr^3＋的^4T2→^4A2跃迁．

Influence of Cr interlayer on the structure and optical properties of Ag films on glass substrate by magnetron sputtering

Optical properties and microstructure of Ag film on glass substrate with Cr intermediate layer were studied by using spectrophotometer and XRD. The spectra results showed that introducing Cr intermediate layer reduced the surface roughness and promoted the reflectivity of Ag film. The XRD analysis showed that the crystalline grains increased and the stress decreased. The adhesion was also improved by using the tape test method. (c) 2006 Published by Elsevier B.V.

Al2O3和Cr过渡层对Ag膜光学性质及其附着力的影响

研究了在玻璃基底上镀制Al2O3和Cr过渡层对Ag膜反射率及附着力的影响.分光光度计测试了Ag膜的反射率,结果表明,与Cr过渡层相比,Al2O3过渡层对Ag膜反射率的降低相对较小;而且,随着Al2O3厚度的增加,Ag膜的反射率先增大后减小.XRD与AES测试表明,引入Al2O3或Cr可明显细化Ag晶粒,减弱Ag膜（111）织构;Al2O3作过渡层时,Al原子向Ag层中扩散显著;而Cr作过渡层时,只有少量Cr原子扩散进入Ag层.因此,Al2O3作过渡层能显著增强薄膜与玻璃基体之间的附着力.