Mechanisms of optical losses in the {sup 5}D{sub 4} and {sup 5}D{sub 3} levels in Tb{sup 3+} doped low silica calcium aluminosilicate glasses

Journal Article · Sat Feb 07 00:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4906781· OSTI ID:22413030

Terra, I. A. A.; Nunes, L. A. O.; Astrath, N. G. C.; Guimarães, F. B.; Baesso, M. L. ^[1]

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1. Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900 Maringá, PR (Brazil)

Trivalent Tb-doped materials exhibit strong emission in the green and weak emission in the UV-blue levels. Usually, this behavior is attributed to the cross relaxation (CR) process. In this paper, the luminescence properties of Tb{sup 3+}-doped low silica calcium aluminosilicate glasses are analyzed for UV (λ{sub exc} = 325 nm) and visible (488 nm) excitations. Under 325 nm excitation, the intensity of green luminescence increases proportionally to Tb{sup 3+} concentration. However, the blue luminescence intensity is strongly reduced with the increase of concentration from 0.5–15.0 wt. %. In the case of 488 nm excitation, a saturation behavior of the green emission is observed at intensities two orders of magnitude smaller than expected for bleaching of the ground state population. Using a rate equation model, we showed that this behavior can be explained by an excited state absorption cross section two orders of magnitude larger than the ground state absorption. The blue emission is much weaker than expected from our rate equations (325 nm and 488 nm excitation). We concluded that only the CR process cannot explain the overall feature of measured luminescence quenching in the wide range of Tb{sup 3+} concentrations. Cooperative upconversion from a pair of excited ions ({sup 5}D{sub 3}:{sup 5}D{sub 3} or {sup 5}D{sub 3}:{sup 5}D{sub 4}) and other mechanisms involving upper lying states (4f5d, charge transfer, host matrix, defects, etc.) may play a significant role.

• OSTI ID: 22413030
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ALUMINIUM SILICATES
CALCIUM COMPOUNDS
CONCENTRATION RATIO
DOPED MATERIALS
EXCITATION
EXCITED STATES
GLASS
GROUND STATES
LUMINESCENCE
PHOTOLUMINESCENCE
QUENCHING
REACTION KINETICS
RELAXATION
SILICA
TERBIUM IONS
ULTRAVIOLET RADIATION
VISIBLE RADIATION