Produção de compósitos metal-dielétrico, a partir de sistemas GeO2 - Bi2O3 dopados com Tm3+ e nanopartí­culas metálicas, para aplicações com guias de onda que atuem como amplificadores na região do infravermelho.

Abstract

During this work, we produced glass samples (in bulk form) with Bi2O3-GeO2 composition. In the first part of the work, we analyzed the preparation conditions. In order to evaluate the influence of the crucible we used alumina (Al2O3) and aluminosilicate (Al2O3-SiO2) crucibles, keeping the concentration of Bi2O3 and melting temperature fixed. To analyze the melt temperature we used the temperature of 1100 °C and 1200 °C keeping the concentration of Bi2O3 and type of crucible fixed. Finally, to analyze the effect of the concentration samples we used different concentrations of 32%, 42% and 62% (in % wt) and the melting temperature and the crucible type remained fixed. The second part of the work consisted in evaluating the energy transfer between the Bi + luminescent centers and the Tm 3+ ions by adding 2% of Tm2O3 in the composition of the Bi2O3-GeO2 glasses, in order to compare the results with those without the rare earth ions. Subsequently, 0.05 wt % of AgNO3 was added to increase the luminescent intensity of thulium ions (Tm 3+) according to the theory of the plasmonic effect as well as the gain at 1470 nm. It was later assembled an arrangement to measure the relative gain of bulk samples Bi2O3-GeO2 doped with thulium oxide (Tm2O3), with and without silver nanoparticles, to justify the application of these glasses as materials to be used in amplifying devices; the use of bulk sample is less expensive than the fabrication of devices and allows us to evaluate previously the material potential. We carried out emission measurements to verify the photoluminescent properties of the material and absorption measurements to verify the concentration of bismuth ions, the silver plasmonic effect, and the incorporation of Tm 3+ ions. TEM (Transmission Electron Microscope) was used to verify the average size of silver nanoparticles and electron diffraction to identify the crystalline structure of the nanoparticles and to prove mainly the presence of silver in the glasses. Enhancement of about 500% was observed for the relative gain that reached 4.5 dB/cm. The reported results show the potential of Bi2O3-GeO2 composite glasses with silver nanoparticles and Tm 3+ for applications requiring intense large bandwidth luminescence in the 1300-1600 nm region and optical amplification at 1470 nm.