Brazilian Journal of Physics
On-line version ISSN 1678-4448
GOUVEIA, E. A.; ARAUJO, M. T. de and GOUVEIA-NETO, A. S.. Thermal effects on light emission in Yb3+-sensitized rare-earth doped optical glasses. Braz. J. Phys. [online]. 2001, vol.31, n.1, pp.89-101. ISSN 1678-4448. http://dx.doi.org/10.1590/S0103-97332001000100017.
The temperature effect upon infrared-to-visible frequency upconversion fluorescence emission in off-resonance infrared excited Yb3+-sensitized rare-earth doped optical glasses is theoretically and experimentally investigated. We have examined samples of Er3+/Yb3+-codoped Ga2S3:La2O3 chalcogenide glasses and germanosilicate optical fibers, and Ga2O3:La2O3 chalcogenide and fluoroindate glasses codoped with Pr3+/Yb3+, excited off-resonance at 1.064mm. The experimental results revealed thermal induced enhancement in the visible upconversion emission intensity as the samples temperatures were increased within the range of 20°C to 260°C. The fluorescence emission enhancement is attributed to the temperature dependent multiphonon-assisted anti-Stokes excitation process of the ytterbium-sensitizer. A theoretical approach that takes into account a sensitizer temperature dependent effective absorption cross-section, which depends upon the phonon occupation number in the host matrices, has proven to agree very well with the experimental data. As beneficial applications of the thermal enhancement, a temperature tunable amplifier and a fiber laser with improved power performance are presented.