Síntese e caracterização de vidros foto-termo-refrativos para aplicações fotônicas e obtenção de monocristais em sistemas vítreos
Carregando...
Data
2019-07-26
Autores
Souza, Antonio Eduardo de
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Sistemas foto-termo-refrativos obtidos a partir de alumino-silicatos dopados com Ce4+, Ag+, Sb3+ e Sn2+ tem sido amplamente estudado nestas últimas década por Glebov e Nikonorov devido a crescente necessidade de desenvolvimento de novos dispositivos que atuem em sistemas ópticos e fotônicos. Estes sistemas produzidos atualmente apresentam índice de refração ~ 1,5 o que limita a observação de efeitos não lineares e transparência na região de baixa energia restrita ao infravermelho próximo. Além disso, como os sistemas atualmente conhecidos são multicomponentes, a compreensão do mecanismo por trás da foto-termo sensibilidade ainda não está completamente elucidada. Neste contexto, a síntese de novas composições de sistemas vítreos, com mecanismos mais simples, com índice de refração mais elevado e transparência na região do infravermelho médio se mostram interessantes pois ampliam as possibilidades de aplicações nas áreas acima citadas. Neste trabalho foram sintetizados e caracterizados vidros foto-termo-refrativos contendo óxidos e oxifluoretos de metais pesados com índice de refração > 2 e transparência desde a região do UV-Vis até o infravermelho médio (~ 7µm). As sínteses foram feitas combinando diferentes óxidos e fluoretos, tais como, Ga2O3, GeO2, PbO, Bi2O3, LaF3 e NaF e utilizando a técnica de fusão seguida de choque térmico, com posterior tratamento térmico controlado. As propriedades térmicas dos novos materiais foram estudadas por calorimetria diferencial de varredura (DSC). As propriedades estruturais foram avaliadas por espectroscopia Raman e difração de raios X, enquanto as propriedades ópticas foram estudadas por espectroscopias nas regiões do infravermelho e UV-Vis além da técnica de M-Lines. As morfologias e as composições químicas foram avaliadas por Microscopia Eletrônica de Varredura (MEV). Um estudo das propriedades fotossensíveis desses materiais foi realizado utilizando um laser de femtosegundo para formar redes de difração e determinar o potencial de vidros como materiais foto-termo-refrativos. A composição 40PbO-20GeO2-25Bi2O3-15Ga2O3 (em% molar) possibilitou a incorporação de 3% em mol de íons terras raras, tais como Er3+, Yb3+ e Tm3+. Estas amostras apresentaram o fenômeno da conversão ascendente de energia na faixa do visível e infravermelho próximo quando excitadas com laser de 980 nm. Estas amostras apresentaram formação de monocristais cúbicos de composição TR3Ga5O12 (TR= terras raras) com propriedades ópticas bem interessantes e que serão explorados futuramente.
Photo-thermo-refractive systems obtained from Alumino-silicates doped with Ce4+, Ag+, Sb3+ and Sn2+ has been extensively studied in recent decades by Glebov and Nikonorov due to the growing need for new devices that act in optical and photonic systems. These systems present refractive index ~ 1.5, which limits the observation of nonlinear effects and as well as the transparency in the region of low energy restricted to near infrared. In addition, as the currently known systems are multi-component, the understanding of the mechanism behind the photo-thermo sensitivity is is complex and not completely elucidated yet. In this context, the synthesis of new vitreous compositions with simplest mechanisms, with higher refraction index and transparency extended up to middle infrared region are interesting because they broaden the possibilities of applications in the areas mentioned above. In this work, we synthesized and characterized photo-thermo-refractive glass containing heavy metals oxides and oxifluorides components with refractive index higher than 2 and transparency window from UV-Vis to the medium infrared (~ 7 µm). The syntheses were made by combining different oxides and fluorides, such as, Ga2O3, GeO2, PbO, Bi2O3, LaF3 and NaF and using the melt-quenching technique with subsequent controlled heat treatment. The thermal properties of the new materials were studied by differential scanning calorimetry (DSC). The structural properties were evaluated by Raman spectroscopy and X-ray diffraction, while the optical properties were studied by spectroscopies in the infrared and UV-Vis regions in addition to the M-Lines technique. Morphologies and chemical compositions were evaluated by scanning electron microscopy (SEM). A study of the photosensitive properties of these materials was performed using a femtosecond laser to form diffraction networks and to determine the potential of glass as photo-thermo-refractive materials. The composition 40PbO-20GeO2-25Bi2O3-15Ga2O3 (in mol %) allowed the incorporation of 3% mol % of rare earth ions, such as Er3+, Yb3+ and Tm3+. These samples presented the phenomenon of upconversion in the visible and near-infrared range when excited with 980 nm laser. These samples showed a formation of cubic crystalline composition RE3Ga5O12 (RE = rare earths) with very interesting optical properties that will be explored in the future.
Photo-thermo-refractive systems obtained from Alumino-silicates doped with Ce4+, Ag+, Sb3+ and Sn2+ has been extensively studied in recent decades by Glebov and Nikonorov due to the growing need for new devices that act in optical and photonic systems. These systems present refractive index ~ 1.5, which limits the observation of nonlinear effects and as well as the transparency in the region of low energy restricted to near infrared. In addition, as the currently known systems are multi-component, the understanding of the mechanism behind the photo-thermo sensitivity is is complex and not completely elucidated yet. In this context, the synthesis of new vitreous compositions with simplest mechanisms, with higher refraction index and transparency extended up to middle infrared region are interesting because they broaden the possibilities of applications in the areas mentioned above. In this work, we synthesized and characterized photo-thermo-refractive glass containing heavy metals oxides and oxifluorides components with refractive index higher than 2 and transparency window from UV-Vis to the medium infrared (~ 7 µm). The syntheses were made by combining different oxides and fluorides, such as, Ga2O3, GeO2, PbO, Bi2O3, LaF3 and NaF and using the melt-quenching technique with subsequent controlled heat treatment. The thermal properties of the new materials were studied by differential scanning calorimetry (DSC). The structural properties were evaluated by Raman spectroscopy and X-ray diffraction, while the optical properties were studied by spectroscopies in the infrared and UV-Vis regions in addition to the M-Lines technique. Morphologies and chemical compositions were evaluated by scanning electron microscopy (SEM). A study of the photosensitive properties of these materials was performed using a femtosecond laser to form diffraction networks and to determine the potential of glass as photo-thermo-refractive materials. The composition 40PbO-20GeO2-25Bi2O3-15Ga2O3 (in mol %) allowed the incorporation of 3% mol % of rare earth ions, such as Er3+, Yb3+ and Tm3+. These samples presented the phenomenon of upconversion in the visible and near-infrared range when excited with 980 nm laser. These samples showed a formation of cubic crystalline composition RE3Ga5O12 (RE = rare earths) with very interesting optical properties that will be explored in the future.
Descrição
Palavras-chave
Vidros foto-termo-refrativos, Up-conversion, Glass-ceramics, Photo-thermo-refractive glass, Vitro-cerâmicas, Conversão ascendente de energia