DIEGO SILVERIO DA SILVA
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
Artigo IPEN-doc 24811 Tunable green/red luminescence by infrared upconversion in biocompatible forsterite nanoparticles with high erbium doping uptake2018 - ZAMPIVA, RUBIA Y.S.; ACAUAN, LUIZ H.; VENTURINI, JANIO; GARCIA, JOSE A.M.; SILVA, DIEGO S. da; HAN, ZHAOHONG; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U.; AGARWAL, ANURADHA; ALVES, ANNELISE K.; BERGMANN, CARLOS P.Nanoparticles represent a promising platform for diagnostics and therapy of human diseases. For biomedical applications, these nanoparticles are usually coated with photosensitizers regularly activated in a spectral window of 530–700 nm. The emissions at 530 nm (green) and 660 nm (red) are of particular interest for imaging and photodynamic therapy, respectively. This work presents the Mg2SiO4:Er3+ system, produced by reverse strike co-precipitation, with up to 10% dopant and no secondary phase formation. These nanoparticles when excited at 985 nm show upconversion emission with peaks around 530 and 660 nm, although excitation at 808 nm leads to only a single emission peak at around 530 nm. The direct upconversion of this biomaterial without a co-dopant, and its tunability by the excitation source, renders Mg2SiO4:Er3+ nanoparticles a promising system for biomedical applications.Artigo IPEN-doc 24381 Production and characterization of femtosecond laser-written double line waveguides in heavy metal oxide glasses2018 - SILVA, DIEGO S. da; WETTER, NIKLAUS U.; ROSSI, WAGNER de; KASSAB, LUCIANA R.P.; SAMAD, RICARDO E.We report the fabrication and characterization of double line waveguides directly written in tellurite and germanate glasses using a femtosecond laser delivering 30 mu J, 80 fs pulses at 4 kHz repetition rate. The double line waveguides produced presented internal losses inferior to 2.0 dB/cm. The output mode profile and the M-2 measurements indicate multimodal guiding behavior. A better beam quality for the GeO2 - Pbo waveguide was observed when compared with TeO2 - ZnO glass. Raman spectroscopy of the waveguides showed structural modification of the glassy network and indicates that a negative refractive index modification occurs at the focus of the laser beam, therefore allowing for light guiding in between two closely spaced laser written lines. The refractive index change at 632 nm is around 10(-4), and the structural changes in the laser focal region of the writing, evaluated by Raman spectroscopy, corroborated our findings that these materials are potential candidates for optical waveguides and passive components. To the best of our knowledge, the two double line configuration demonstrated in the present work was not reported before for germanate or tellurite glasses.