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Master's Dissertation
DOI
10.11606/D.76.1999.tde-12092007-174322
Document
Author
Full name
Sandro Marcio Lima
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1999
Supervisor
Committee
Catunda, Tomaz (President)
Faria, Roberto Mendonça
Zanotto, Edgar Dutra
Title in Portuguese
Aplicações da técnica de lente térmica em materiais ópticos.
Keywords in Portuguese
Propriedades termo-ópticas
Técnica de lente térmica
Vidros calcogenetos
Vidros fluorestos
Abstract in Portuguese
Neste trabalho, a técnica de Lente Térmica (LT) foi usada para determinar o valor absoluto da difusividade térmica (D), da condutividade térmica (K) e do coeficiente de temperatura do caminho óptico (ds/tD) de vidros fluoretos dopados com cobalto e neodímio, calcogenetos, calcohaletos (mistura de calcogenetos com haletos), aluminate de cálcio e de um cristal fluoreto. Estas medidas foram efetuadas na temperatura ambiente e próxima de Tg para algumas amostras. Para o vidro ZBLAN, realizamos experimentos de LT da temperatura ambiente até ~ 330°C, observando um grande decréscimo de D na região de transição do vidro (Tg ~ 290°C). Nós também aplicamos a técnica de LT para determinar a eficiência quântica fluorescente do ZBLAN dopado com Nd+3. A utilidade desta técnica para determinar as propriedades termo-ópticas dos materiais transparentes em função da temperatura foi demonstrado.
Title in English
Applications of the thermal lens technique in optical materials
Keywords in English
Chalcogenide glasses
Fluoride glasses
Thermal lens technique
Thermo-optical properties
Abstract in English
In this work the Thermal Lens (TL) technique was used to determine the absolute values of the thermal diffusivity (D), thermal conductivity (K) and temperature coefficient of the optical path length (ds/dT) of fluoride, chalcogenide, chalcohalide (chalcogenides and halides mixture) and calcium aluminate glass and of a fluoride cristal. These measurements were developed at ambient temperature and near Tg for some samples. For the ZBLAN glass, we performed the TL experiment from ambient to ~ 330°C, observing na abrupt decrease on D close to the glass transition temperature (Tg ~ 290°C). We also applied the TL technique to determine the fluorescence quantum efficiency of Nd+3 doped ZBLAN. The usefulness of this technique to determine thermo-optical properties of transparent materials as a function of the temperature was demonstrated.
 
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SandroLima.pdf (3.20 Mbytes)
Publishing Date
2007-09-14
 
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