High pressure fluorescence studies of Sm³⁺-doped K–Ba–Al phosphate glass

Abstract

Pressure-induced fluorescence spectra and decay curves for the ⁴G_5/2 level of Sm³⁺ ions in P₂O₅+K ₂O+BaO+Al ₂O ₃ glass have been studied up to 24.4 GPa at room temperature. The study reveals that ⁴G_5/2→⁶H _J (J=9/2, 7/2 and 5/2) emission band positions are shifted to lower energy (red shift) in the order of 2.4, 2.6 and 2.7 cm⁻¹ per GPa, respectively. The increase in Stark level splittings has also been noticed with increasing pressure for the emission bands mentioned above. The decay profiles show increased non-exponential behaviour at higher pressures accompanied by a shortening of lifetimes. The non-exponential decay curves were fitted to the Inokuti–Hirayama model. The decrease in the lifetime with an increase in pressure is caused by an increase in the electronic transition probabilities. This is a result of the increased crystal-field strength around Sm³⁺ ions. The original results obtained after the release of pressure confirm that no structural hysteresis takes place around the Sm³⁺ ions.

Keywords:

• Glass
• Optical materials
• Energy transfer
• Structural properties
• Crystal-field

Acknowledgements

This work has been carried out under the financial assistance of a major research project sponsored by DAE-BRNS, Government of India (no. 2003/34/4-BRNS/600, dt. 11-07-2003). C. K. Jayasankar is grateful to Department Physik, Universität Paderborn, Germany also for his stay as a Guest Scientist.