Palestrante
Descrição
Optical temperature sensors enable fast and long-distance measurements in environments where standard contact sensors are ineffective, such as electrical power stations (strong electromagnetic fields), electronic circuits and biological cells (sub-micron scale). (1) These devices are based on temperature induced changes in optical properties of a given material. The fluorescence intensity ratio technique (FIR) makes use of the relative emission intensity variation of two thermally coupled levels of an emission center, usually a trivalent rare-earth ion (RE$^{3+}$). (2) Neodymium (Nd$^{3+}$) is commonly employed as its emissions lie in the near-infrared biological optical window and don’t show much overlap. In this work, Nd$^{3+}$-doped and Nd$^{3+}$/Yb$^{3+}$-co-doped fluorophosphate glasses with excellent optical and spectroscopic properties (3) are employed as the temperature sensing material. Sensibilities as high as 1.96%/K are obtained through the FIR of 800 and and 870 nm Nd$^{3+}$ emissions. The use of the emission ratio of 750 and 870 nm was also investigated and results in even higher sensibilities. The addition of ytterbium (Yb$^{3+}$) to the glasses makes the sensibilities increase to 2.77%. Further analysis involved the ideal glass matrix characteristics to enhance the system’s performance, the phonons role in the energy transfer between the ions and the energy transfer pathways. Other RE$^{3+}$ pairs exhibiting strongly temperature dependent energy transfer rates are indicated.
Referências
1 BRITES, C. D. S. et al. Thermometry at the nanoscale. Nanoscale, v. 4, n. 16, 4799-4829, Aug. 2012.
2 WADE, S. A.; COLLINS, S. F.; BAXTER, G. W. Fluorescence intensity ratio technique for optical fiber point temperature sensing. Journal of Applied Physics, v. 94, n. 8, p. 4743-4756, Oct. 2003.
3 GONÇALVES, T. S. et al. Structure-property relations in new fluorophosphate glasses singly- and co-doped with Er$^{3+}$ and Yb$^{3+}$. Materials Chemistry and Physics, v. 157, p. 45-55, May 2015. doi: 10.1016/j.matchemphys.2015.03.012.
| Subárea | Espectroscopia |
|---|---|
| Apresentação do trabalho acadêmico para o público geral | Não |
