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Luminescence properties of Eu3+-doped Al2(WO4)3

Macalik L., Hanuza J., Hermanowicz K., Godlewska P., Sidorov N. V.

Materials Science Poland

2004

Vol. 22, No. 2

145--152

Emission spectra of Al2(WO4)3 doped with Eu3+ were recorded at room temperature (orthorhombic phase) and at 10 K (monoclinic phase). The luminescence excitation spectra and luminescence decay profiles were recorded for both structural modifications at RT and LN2T, and the luminescence lifetimes of Eu3+ have been estimated. Two-site behaviour of the optically active ions in both phases has been revealed in the luminescence studies. However, the emission decay profiles give one lifetime of the 5D2 level, equal to 1.8 ms and 848.4 žs at room temperature and liquid nitrogen temperature, respectively. The results obtained have been explained in terms of an unusual location of Eu3+ ions inside the crystal tunnels, parallel to the c-axis.

Optical absorption and luminescence of LiTaO₃:Cr and LiTaO₃:Cr, Nd crystals

Gołąb S., Sokólska I., Dominiak-Dzik G., Palatnikov M. N., Sidorov N. V., Biryukova I., Kalinnikov V. T., Ryba-Romanowski W.

Opto-Electronics Review

1999

Vol. 7, No. 2

145-147

The interest in LiNbO₃ and LiTaO₃ crystals doped with transition metal or rare eartch ions is related to their potential applications as self-switching and self-frequency doubling laser materials. In the past considerable attention has been paid to LiNbO₃ crystals doped by variety of luminescent ions. In particular LiNbO₃:Cr was investigated recently by Macfarlane et al. [1]. Energy transfer between Cr³⁺ and Nd³⁺ in LiNbO₃ has been studied and discussed by Vergara et al. [2]. In this work we investigate spectroscopic properties of Cr³⁺ and Cr³⁺ - Nd³⁺ interaction in LiTaO₃ using optical absorption, luminescence and luminescence decay times at temperatures between 5 K and 300 K. Some preliminary data obtained with singly doped LiTaO₃:Cr at low activator concentration are given in our previous work [3]. Recorded spectra indicate that both the Cr³⁺ and Nd³⁺ are located in several non - equivalent sites that differ in the strength of the crystal field. Luminescence spectrum of Cr³⁺ consists of a broad band whose maximum and intensity depend on temperature. Below about 50 K an additional sharp band with four distinct components appears in the spectrum. The broad band attributed to the spin allowed ⁴T₂ - ⁴A₂ transition of Cr³⁺ ions overlaps two absorption bands of Nd³⁺ ions at about 810 nm and 890 nm making the Cr³⁺ - Nd³⁺ energy transfer process feasible. Results of measurements are discussed and compared to those obtained with LiNbO₃:Cr.