Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (09): 1059-1062.doi: 10.3866/PKU.WHXB20050923

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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


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