物理化学学报 >> 2005, Vol. 21 >> Issue (09): 1059-1062.doi: 10.3866/PKU.WHXB20050923

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Ca3Al2Ge3O12:Cr3+的光谱性质及晶场参数计算

袁剑辉; 程玉民; 张振华   

  1. 长沙理工大学物理与电子科学系, 长沙 410076; 上海大学, 上海市应用数学和力学研究所, 上海 200072
  • 收稿日期:2005-01-20 修回日期:2005-04-19 发布日期:2005-09-15
  • 通讯作者: 袁剑辉 E-mail:yuanjianhui2003@163.com

Spectral Properties and Crystal Field Parameters of the Cr3+ Ions in Ca3Al2Ge3O12 Germanate Garnet

YUAN Jian-hui; CHENG Yu-min; ZHANG Zhen-hua   

  1. Department of Physics and Electronic Science, Changsha University of Science & Technology, Changsha 410076; Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072
  • Received:2005-01-20 Revised:2005-04-19 Published:2005-09-15
  • Contact: YUAN Jian-hui E-mail:yuanjianhui2003@163.com

摘要:

为了解Cr3+离子在钙铝锗酸盐Ca3Al2Ge3O12:石榴石中的光谱性质, 合成了Ca3Al2Ge3O12:Cr3+多晶材料;测量了其X射线衍射图, 漫反射光谱, 激发、发射光谱等;分析了Cr3+离子在钙铝锗酸盐中的发光特性;计算了其晶场强度(Dq/B), Stokes位移(ΔEs)及黄昆-里斯因子(S)等. 在450 nm激发下, Ca3Al2Ge3O12:Cr3+室温发射光谱主要由三个宽带及附加其上的弱R线构成, 分别对应于Cr3+离子的4T1、 4T2、2T2到 4A2 能级跃迁. 低温时R线变得强而锐. 通过计算, Dq/B=2.43, ΔEs=1884 cm-1, S=5.21. 表明在Ca3Al2Ge3O12中Cr3+离子处于较弱的晶场强度, 电子-声子耦合较强, 为发展可调谐激光材料提供重要线索.

关键词: 光谱学;Ca3Al2Ge3O12:Cr3+;宽带发射;晶场参数;可调谐激光材料

Abstract:

In order to investigate the spectral properties of the Cr3+ in Ca3Al2Ge3O12: garnet, the polycrystal material Ca3Al2Ge3O12:Cr3+ was synthesized; its X-ray diffraction patterns, diffuse reflection spectra, excitation and emission spectra were measured. The spectral properties of the material were discussed and the crystal field strength (Dq/B), Stokes displacements(ΔEs) along with Huang-Rhys factors(S) were calculated. Under the excitation of 450 nm light, the emission spectrum of Cr3+ in Ca3Al2Ge3O12 garnet at room temperature mainly consists of three broad bands with weak R line. Three broad bands correspond to 4T1-4A2, 4T2-4A2, and 2T2-4A2 transitions of Cr3+ ions, respectively. The R line becomes stronger and sharper at low temperature of 30 K. The calculated results showed Dq/B=2.43, ΔEs=1884 cm-1 and S=5.21, indicating that Cr3+ ions in Ca3Al2Ge3O12: garnet locate at weaker crystal field strength and the coupling between the electrons and the phonons is strong. The results imply that Ca3Al2Ge3O12:Cr3+ would be a promising material for tunable laser.

Key words: Spectroscopy;Cr3+ doped calcium aluminium germanate garnet;Broad-band emission;Crystal field parameter;Tunable laser material