Absorption and emission of ErNbO 4 powder

• Published in: Optical materials Vol. 25; no. 4; pp. 379 - 392
• Main Authors: Zhang, De-Long, Wang, Yu-Fang, Pun, E.Y.B, Yu, Yi-Zhong, Chen, Cai-He, Yao, Jian-Quan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2004
• Subjects: Absorption; Emission; ErNbO 4; 42.70.−a; 78.40.Ha; 78.55.Hx; 78.30.Hv; Absorption; Emission; ErNbO 4
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2003.09.004

Visible and near infrared absorption and emission (488 nm excitation) characteristics of ErNbO 4 powder, which were prepared by calcining the Er 2O 3 (50 mol%) and Nb 2O 5 (50 mol%) powder mixture at 1100 and 1600 °C for different durations, have been investigated at room temperature. The absorption and emission characteristics of these calcined ErNbO 4 powder were summarized and discussed in comparison with those of Er 2O 3. Weak emission of Er 2O 3 relative to the calcined ErNbO 4 is mainly conducted with absorption difference at the excitation wavelength 488 nm. The obvious spectral changes from Er 2O 3 to calcined ErNbO 4 samples are related to an elevated-temperature-assisted phase transformation according to the solid-state chemical reaction equation: Er 2O 3 + Nb 2O 5 ⇌ 2ErNbO 4, which results in the changes of the ion environment of Er 3+ and hence changes of the Stark levels of Er 3+. The further spectral change as the strengthened calcination results from the improvement of ErNbO 4 purity in the calcined mixture. The borders between two green transitions and between two near infrared transitions in the emission spectra of both calcined samples and Er 2O 3 were tentatively identified by referencing earlier reported emission spectra of the precipitated Z-cut VTE Er(2.0 mol%):LiNbO 3 crystal and the match relation between absorption and emission spectra of the ErNbO 4 powder. A comparison was performed on the spectra of calcined ErNbO 4 powder and those of VTE Er(2.0 mol%):LiNbO 3 crystals. The results allow to preliminarily deem the contribution of ErNbO 4 precipitates, generated inside these crystals by the VTE procedure, to the spectra of these crystals.