Spectroscopic characteristics of langasite (La3Ga5SiO14) and langatate (La3Ga5.5Ta0.5O14) crystals doped with Eu3+

✍ Scribed by S. Georgescu; O. Toma; A.M. Chinie; L. Gheorghe; A. Achim; A.S. Stefan

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 241 KB
• Volume: 30
• Category: Article
• ISSN: 0925-3467
• DOI: 10.1016/j.optmat.2007.05.035

✦ Synopsis

The spectroscopic properties of two partially disordered crystals langasite (LGS) and langatate (LGT) doped with Eu 3+ were investigated. The fluorescence lifetimes of 5 D 0 and 5 D 1 excited levels are measured. The spectroscopic figures of merit R 0 , R 2 (the areas of the electric-dipole transitions 5 D 0 ! 7 F 0 and, respectively, 5 D 0 ! 7 F 2 divided by the area of the magnetic-dipole one -5 D 0 ! 7 F 1 ) and the maximum splitting of the 7 F 1 level (DE) are calculated from the luminescence spectra. The spectral overlapping between the luminescence from 5 D 0 and 5 D 1 levels was eliminated using pulsed excitation at 532 nm and suitable delays. We obtained R 0 (LGS) > R 0 (LGT), R 2 (LGS) < R 2 (LGT) and DE (LGS) > DE (LGS). Possible reasons (covalency, J-mixing effects) for these inequalities are discussed.