Influence of Zn2+ ions concentration on the optical properties of Zn/Er:LiNbO3 crystals

✍ Scribed by Yannan Qian; Rui Wang; Lili Xing; Yanling Xu; Chunhui Yang; Xinrong Liu

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 210 KB
• Volume: 46
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.201100254

✦ Synopsis

LiNbO 3 crystal, optical characteristic, defect structure.

Congruent Er 3+ (3 mol%):LiNbO 3 crystals codoped with ZnO (X mol%, X=0, 3, 6 and 7) were grown by the Czochralski technique. The Er contents in the crystals were measured by an inductively coupled plasma atomic emission spectrometer (ICP-AES). Under 800 nm excitation, the upconversion emission spectra reveal an enhancement of the green emission with respect to the red emission when the Zn 2+ ions are introduced into Er:LiNbO 3 crystal. The effect of Zn 2+ ions concentration on the intensity ratio of the green to red emission has been investigated. Two cross-relaxation processes ( 2 H 11/2 + 4 I 13/2 → 4 I 11/2 + 4 F 9/2 and 4 F 7/2 + 4 I 11/2 → 4 F 9/2 + 4 F 9/2 ) are involved in populating the 4 F 9/2 state, which bypass the green-emitting states. The OH -absorption spectra indicate that the Zn 2+ codoping leads to a decreased concentration of Er 3+ cluster sites contributing to the enhancement of the green emission. The studies on UV-vis absorption spectra show that the heavily codoped with Zn 2+ results in the reformation of the Er 3+ cluster sites in Er:LiNbO 3 .