Now showing items 1-7 of 7
| Abstract: | The advent of high optical quality transparent nano—structured glasses, the so-called transparent glass ceramics or vitroceramics disclosed the possibility of producing nano-sized photonic devices based on rare-earth doped up—converters. Transparent glass ceramics have been investigated as hosts for lanthanide ions envisioning the production of materials that are easy to shape and with high performance for photonic applications. Rare earth doped glasses have been extensively studied due to their potential applications in optical devices such as solid state lasers and optical fibers. Various photothermal and optical techniques have been successfully applied for the thermal and optical characterization of these rare earth doped materials. In the present thesis, the effective thermal parameters like thermal diffusivity and thermal effusivity of complex materials for various applications have been investigated using photothermal methods along with their optical characterization utilising the common optical absorption as well as fluorescence spectroscopic techniques. These sensitive optical procedures are also essential for exploiting these materials for further photonic applications. |
| Description: | School of photonics, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3455 |
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| Dyuthi-T1466.pdf | (7.162Mb) |
| Abstract: | The photosensitivity of dye mixture-doped polymethyl methacrylate (PMMA) films are investigated as a function of laser power, concentration of the dyes, modulation frequency and the irradiation wavelength. Energy transfer from a donor molecule to an acceptor molecule affects the emission output of the dye mixture system. Photosensitivity is found to change with changes in donor–acceptor concentrations. PMMA samples doped with the dye mixture are found to be more photosensitive when the dyes are mixed in the same proportion. |
| URI: | http://dyuthi.cusat.ac.in/purl/2510 |
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| Dyuthi-P0133.pdf | (277.0Kb) |
| Abstract: | The laser-induced luminescence studies of the rare earth titanates (R2Ti2O7) (R = La, Nd and Gd) using 355 nm radiation from an Nd:YAG laser are presented. These samples with submicron or nanometer size are prepared by the self-propagating high temperature synthesis (SHS) method and there is no known fluorescence shown by these rare earths in the visible region. Hence, the luminescence transitions shown by the La2Ti2O7 near 610 nm and Gd2Ti2O7 near 767 nm are quite interesting. Though La3+ ions with no 4f electrons have no electronic energy levels that can induce excitation and luminescence processes in the visible region, the presence of the Ti3+ ions leads to luminescence in this region. |
| URI: | http://dyuthi.cusat.ac.in/purl/2583 |
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| Dyuthi-P0143.pdf | (741.3Kb) |
| Abstract: | Laser induced photoacoustic (PA) technique is used in the study of photostability of polymethyl methacrylate (PMMA) films doped with Rhodamine 6G -Rhodamine B dye system. Energy transfer from a donor molecule to an acceptor molecule in a dye mixture affects the output of the dye system. Details of investigations on the role of laser power, modulation frequency and the irradiation wavelength on the photosensitivity of the dye mixture doped PMMA films are presented. |
| URI: | http://dyuthi.cusat.ac.in/purl/618 |
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| pmrp7.pdf | (82.50Kb) |
| Abstract: | Thermal characterization of alumina–zirconia and zirconia ceramic tapes using a photoacoustic technique is presented. A transmission-mode geometry is employed for the measurement of thermal diffusivity while a reflection-mode geometry is used for the measurement of thermal effusivity. In both these geometries, the same open photoacoustic cell is used. From the measured values of thermal diffusivity and thermal effusivity, the thermal conductivity value has also been evaluated. |
| URI: | http://dyuthi.cusat.ac.in/purl/2612 |
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| Dyuthi-P0172.pdf | (353.2Kb) |
| Abstract: | Thermal diffusivity (TD) measurement on commercial K-10 and KSF montmorillonites was carried out by photoacoustic technique. The TD of the montmorillonites after methylene blue adsorption changed with the dye concentration. The repeatedly adsorbed samples showed a lesser TD than the single adsorbed samples. After methylene blue adsorption the acid leached K-10 samples showed well defined changes in TD when compared to the ordered KSF samples |
| Description: | Applied Clay Science 42 (2009) 483–487 http://dx.doi.org/10.1016/j.clay.2008.06.006 |
| URI: | http://dyuthi.cusat.ac.in/purl/3999 |
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| Thermal charact ... ed montmorillonites by.pdf | (325.8Kb) |
| Abstract: | Thermal diffusivity (TD) measurement on commercial K-10 and KSF montmorillonites was carried out by photoacoustic technique. The TD of the montmorillonites after methylene blue adsorption changed with the dye concentration. The repeatedly adsorbed samples showed a lesser TD than the single adsorbed samples. After methylene blue adsorption the acid leached K-10 samples showed well defined changes in TD when compared to the ordered KSF samples. |
| URI: | http://dyuthi.cusat.ac.in/purl/1756 |
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| pdf 3.pdf | (325.8Kb) |
Now showing items 1-7 of 7
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