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Relations entre propriétés spectroscopiques et microstructurales de couches minces de titanates de terres rares élaborées par sol-gel et intégration dans des dispositifs actifs

Abstract : The development of rare earth-doped thin films has gained interest over these last few years. In this report, we present the elaboration of Y2-xLnxTi2O7 thin films (Ln=Er, Tm, Yb, Nd) by the Aerosol-gel process and their characterisation. The aerosol-gel process is an original deposition technique based on the sol-gel transformation of a liquid film deposited by ultrasonic pulverisation. Various heat-treatment procedures have been investigated in order to study the influence of the film microstructure on the related spectroscopic properties. The films were found to crystallise in a single cubic pyrochlore phase at around 750-785°C, depending on the heat-treatment duration. Crystalline and amorphous Y2-xErxTi2O7 (YETO) thin films exhibit a strong emission at 1530 nm when excited at 977 nm in a waveguiding configuration. A clear relationship was established between the films microstructure and their spectroscopic properties. Elaboration of a YETO solid solution enables a homogeneous dilution of erbium ions and efficiently prevents them from interactions with residual impurities. The quenching concentration of crystalline films is far greater (9. 1020 ions/cm3) than that of amorphous films (2. 1020 ions/cm3). Ytterbium codoping of YETO films enhances the emission of erbium ions at 1530 nm by a factor 10, as well as their up-conversion emission in the green region. Amorphous Y2-x-yTmxYbyTi2O7 films were also elaborated and exhibited a strong blue up-conversion emission when excited at 977 nm. YETO films were introduced in elementary optical devices. Confined waveguides (built-in strip waveguide and strip-loaded waveguide) were fabricated and characterised. They show a good emission at 1530 nm and a good optical confinement. A vertical microcavity was also elaborated by inserting a half wave YETO thin film between two Bragg mirrors formed by alternations of SiO2/TiO2 layers. The cavity presents a single mode resonance at 525 nm, and the erbium emission at this wavelength is increased by a factor 30.
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https://tel.archives-ouvertes.fr/tel-00004400
Contributor : Pierre Jenouvrier <>
Submitted on : Thursday, January 29, 2004 - 8:52:16 PM
Last modification on : Thursday, November 19, 2020 - 12:59:39 PM
Long-term archiving on: : Friday, April 2, 2010 - 7:44:22 PM

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Pierre Jenouvrier. Relations entre propriétés spectroscopiques et microstructurales de couches minces de titanates de terres rares élaborées par sol-gel et intégration dans des dispositifs actifs. Physique Atomique [physics.atom-ph]. Institut National Polytechnique de Grenoble - INPG, 2003. Français. ⟨tel-00004400⟩

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