The main aim of this thesis was to contribute with detailed information of regional environmental change during the Holocene through studies of speleothems and their growth environments from two caves, Korallgrottan and Labyrintgrottan in northwestern Sweden, and a cellar vault in Uppsala. This was done through studies of stable isotopes and luminescence properties in the speleothems in combination with a detailed monitoring study in Korallgrottan. The monitoring study suggests that stalagmites fed by stalactites with slow and stable drip rates from deep inside the cave may be suitable as palaeoclimate archives. Similarities between oxygen isotope signals of contemporary samples from Labyrintgrottan and Korallgrottan emphasize the potential of speleothems from Labyrintgrottan to also provide high resolution regional palaeoclimate information. Except for a number of cold events stalagmite δ18O records from northern Scandinavia indicate that temperatures were warmer than today between 9500 and 6000 years ago. During this period the interval between 7800 and 6000 years ago seems to have been the warmest. The area above Labyrintgrottan was most likely covered by much denser vegetation than today at the time of stalagmite growth (9500-7500 years ago) and was, unlike today, probably situated below the local tree-limit between 9000 and 8000 years ago. The δ18O record of a stalagmite from Korallgrottan covering the last 4000 years agrees with the concept of a warmer period, the so called Medieval Warm Period, centred around AD1000 and a colder period, the so called Little Ice Age, somewhere between AD1000 and today. Studies of luminescence properties in fast growing speleothems from Uppsala indicate that the variations in luminescence intensity are annual and that the annual lamiae of the luminescent record represent a flush of organic material.

Dans le cadre de l'optimisation des luminophores destinés aux lampes fluorescentes, nous nous sommes intéressés plus particulièrement au luminophore bleu Ba0.9Eu0.1MgAl10O17. Les travaux présentés dans ce mémoire débutent par l'étude de l'influence de quelques fondants sur la microstructure et le rendement de luminescence. Nous avons également étudié l'impact de ces fondants sur les propriétés cristallographiques du matériau et les conséquences sur les propriétés optiques. Dans un deuxième temps nous sommes intéressés à un problème qui subsiste depuis plusieurs années : la perte de luminescence lors de la fabrication des lampes due à l'oxydation du dopant lors du baking (recuit sous air à haute température). Si la cause de cette dégradation est connue, les mécanismes ne le sont toujours pas précisément. Afin de proposer une solution industrielle fiable et applicable, nous devons d'abord comprendre les phénomènes. En combinant diverses techniques d'analyses nous avons eu une nouvelle approche pour expliquer le mécanisme de dégradation, ce qui nous a permis de compléter les études déjà existantes. Au terme de ces travaux, nous avons également proposé une solution que nous pensons directement applicable en industrie mais qu'il reste à optimiser. Enfin, nous avons choisi de rester sur le même matériau pour étudier le vieillissement de tubes fluorescents bleus. Nos résultats montrent que la perte de mercure est la cause principale de la baisse de performances des lampes, et notre étude peut donc s'étendre à d'autres luminophores et aux lampes trichromatiques.

Les nanocristaux à luminescence persistante ont récemment été introduits dans le domaine de l'imagerie optique du petit animal comme alternative originale aux systèmes photoluminescents couramment utilisés pour la détection photonique in vivo. Comparables à des condensateurs optiques, ces matériaux présentent l'avantage de pouvoir être excités avant l'injection au petit animal, puis d'émettre un signal de luminescence dans la fenêtre de transparence des tissus, sans excitation continue de la sonde, pendant plusieurs dizaines de minutes. Cette technique propose une solution efficace au problème d'autofluorescence rencontré in vivo du fait de l'excitation des tissus biologiques, et permet d'augmenter de manière significative le rapport signal à bruit au moment de la détection optique. Les travaux initiaux ont cependant démontré que cette première génération de nanocristaux pouvait difficilement être suivie plus d'une heure après injection systémique chez le petit animal, et subissait une capture rapide au niveau du foie par le système monocyte macrophage. Pour répondre à ces deux inconvénients majeurs, nous introduisons une nouvelle génération de nanosondes photoniques dont les propriétés optiques permettent une excitation de la luminescence persistante in vivo, à travers les tissus de l'animal. Il devient ainsi possible de recharger le matériau après son injection à la souris et de retrouver un signal de luminescence persistante à tout moment. Une optimisation des propriétés de surface a également permis d'augmenter de manière significative le temps de circulation de ces nanoparticules, et de réaliser la première preuve de ciblage passif in vivo qui exploite l'effet EPR.

Metal organic framework (MOF) has emerged as a new class of porous, thermally stable material which has attracted great attention due to their wide applications in gas storage, separation, catalysis etc. Self-assembly is the operative mechanism of MOFs syntheses; however, the control of MOF self-assembly is still a challenge in the construction of predetermined, structurally well-defined MOFs. The goal of the research is to arrive at multidimensional, highly porous and functional MOFs via hierarchical assembly of smaller molecular building blocks and, at the same time, to examine the possibilities for different interesting molecular textures. This goal is to be accomplished by the knowledge of ligand coordination mode, and geometry as well as logical choices of ligands and metals from which the MOFs are to be constructed from. Preparations of novel frameworks as well as other interesting molecular architectures are highlighted with their structures characterized.

Detection modalities that can evaluate the early stages of dental caries are indispensable. The purpose of this thesis is to evaluate the efficacy of photothermal radiometry and modulated luminescence (PTR-LUM) to non-destructively detect and quantify simulated enamel caries. Two experiments were performed based on the PTR-LUM detection mode: back-propagation or transmission-mode. Artificial demineralized lesions were created in human molars and a subset was further exposed to an artificial remineralizing solution. PTR-LUM frequency scans were performed periodically during de/re-mineralization treatments. PTR data was fitted to a theoretical model based on optical and thermal fluxes in enamel to extract opto-thermophysical parameters. Lesion validation was performed using transverse microradiography (TMR). Optical and thermal properties changed with the development and repair of the caries lesions while theory-derived thicknesses paralleled those determined microradiographically. These trends coupled with the uniqueness-of-fit of the generated parameters illustrate the efficacy of PTR- LUM to non-destructively detect and quantify de/re-mineralized lesions.

Detection modalities that can evaluate the early stages of dental caries are indispensable. The purpose of this thesis is to evaluate the efficacy of photothermal radiometry and modulated luminescence (PTR-LUM) to non-destructively detect and quantify simulated enamel caries. Two experiments were performed based on the PTR-LUM detection mode: back-propagation or transmission-mode. Artificial demineralized lesions were created in human molars and a subset was further exposed to an artificial remineralizing solution. PTR-LUM frequency scans were performed periodically during de/re-mineralization treatments. PTR data was fitted to a theoretical model based on optical and thermal fluxes in enamel to extract opto-thermophysical parameters. Lesion validation was performed using transverse microradiography (TMR). Optical and thermal properties changed with the development and repair of the caries lesions while theory-derived thicknesses paralleled those determined microradiographically. These trends coupled with the uniqueness-of-fit of the generated parameters illustrate the efficacy of PTR- LUM to non-destructively detect and quantify de/re-mineralized lesions.

Metal organic framework (MOF) has emerged as a new class of porous, thermally stable material which has attracted great attention due to their wide applications in gas storage, separation, catalysis etc. Self-assembly is the operative mechanism of MOFs syntheses; however, the control of MOF self-assembly is still a challenge in the construction of predetermined, structurally well-defined MOFs. The goal of the research is to arrive at multidimensional, highly porous and functional MOFs via hierarchical assembly of smaller molecular building blocks and, at the same time, to examine the possibilities for different interesting molecular textures. This goal is to be accomplished by the knowledge of ligand coordination mode, and geometry as well as logical choices of ligands and metals from which the MOFs are to be constructed from. Preparations of novel frameworks as well as other interesting molecular architectures are highlighted with their structures characterized.

En vue d'application à l'éclairage ou dans les dispositifs de visualisation à plama, on a étudié la luminescence de l'ion Eu2+ dans les borates BaLnB9O16 (Ln = La, Ce, Gd, Y) et de l'ion Eu3+ dans les diverses phases des systèmes Gd2O3-P2O5 et Y2O3-P2O5. Des informations sur les structures des réseaux-hôtes lorsqu'elles étaient inconnues, ont pu être obtenues par diffraction X et spectroscopie Raman. Pour Ln = Y, Gd, les borates BaLnB9O16:Eu2+ présentent une émission dans le bleu stable...

Síntesis, caracterización y estudio de las propiedades luminiscentes y magnéticas de complejos pentacoordinados de níquel(II) con ligandos orgánicos del tipo: 8-hidroxiquinolinas, imidas, benzazoles y ácidos mono- y dicarboxílicos. Utilización de estos complejos como sensores luminiscentes en la detección de cationes metálicos de interés biológico y/o ambiental.

Esta tesis describe el diseño, la fabricación y la caracterización óptica de sistemas plasmónicos resonantes capaces de confinar y aumentar campos de luz en la escala manométrica. En primer lugar, se utilizaron modelos numéricos 3D para diseñar diferentes geometras de nanoestructuras plasmónicas acopladas, a través del cálculo de la respuesta óptica de su campo lejano y cercano. Sobre la base de estas simulaciones se fabricaron las nanoestructuras por litografía de haz electrónico. Se puso especial énfasis en el aumento de la resolución y la optimización de la reproducibilidad de parámetros críticos como la forma de las partículas y el gap entre ellas. Por último, se empleó espectroscopía de campo lejano combinada con espectroscopía de luminiscencia inducida por dos fotones (TPL) para sondar la respuesta óptica local de las geometrías optimizadas. Hemos centrado nuestra atención en diferentes tipos de estructuras metálicas: dímeros, antenas con gap, conjuntos finitos de partículas en cadenas y en forma de estrella. Los dímeros tienen una fuerte amplificación del campo en su gap nanométrico por el acoplamiento en campo cercano de sus resonancias plasmonicas dipolares. Análogamente, antenas con gap, formadas por dos barras de oro adyacentes que soportan resonancias multipolares, pueden acoplar de manera eficiente la luz y concentrarla en volúmenes pequeños. Se ha demostrado que cadenas finitas de partículas son buenos candidatos para guiar la luz a través de secciones transversales por debajo de la longitud de onda y aquí demostramos que también se pueden utilizar como nanolentes capaces de concentrar la luz en su extremo. La distribución del campo cercano en conjuntos de partículas de oro en forma de estrella presenta una fuerte dependencia con la polarización del campo incidente que puede ser explotada para dirigirse dinámicamente a nano-objetos. La espectroscopía de campo lejano de conjuntos de dímeros y de cadenas finitas de partculas se comparó con la espectroscopía de TPL. Nuestro principal resultado es mostrar que la TPL es preferentemente sensible a los campos locales, permitiendo evaluar características espectrosc ópicas que no podrían resolverse de otro modo. A fin de superar las limitaciones de las medidas de conjuntos, en una segunda etapa se dedicó un considerable esfuerzo a construir y optimizar un montaje óptico para medir la señal de TPL de estructuras únicas. El uso de la micro-espectroscopía de TPL permitió obtener mapas espectrales de los modos de antenas aisladas con resolución espacial. Como se predijo mediante cálculos, hemos sido capaces de visualizar directamente, en la resonancia, la señal de TPL amplificada dentro del gap. Nuestros resultados muestran cómo las medidas de TPL pueden compararse directamente con la distribución de la cuarta potencia del campo local calculado. Mediante el análisis de la evolución de la señal de TPL en función de la longitud de onda incidente en el gap y en las extremidades de la antena tenemos más conocimiento sobre el mecanismo físico detrás de la resonancia de la antena. Finalmente, la microscopía de TPL se utilizó para sondar el campo cercano para diferentes orientaciones de la polarización lineal incidente sobre los conjuntos de partículas en forma de estrella. Se demuestra que, a diferencia del espectro de dispersión, la distribución de TPL en la estructura depende drásticamente del estado de polarización incidente. Nuestro estudio aporta una contribución significativa al campo de la óptica de plasmones, proponiendo nuevas geometrías para confinar de manera eficiente los campos ópticos a la escala nanometrica, aportando un profundo conocimiento sobre el uso de micro-espectroscopa de TPL como sonda óptica local. Nuestros resultados tendrán importancia en aplicaciones tales como espectroscopía mejorada, biosensores y la interacción luz-materia, donde se necesita evaluar el campo experimentado por una pequeña cantidad de materia cercana a la nanoestructura. / This thesis describes the design, fabrication and the optical characterization of plasmon-resonant systems able to confine and enhance light fields down to the sub-wavelength scale. Extensive 3D numerical modeling was first used to design different geometries of coupled plasmonic nanostructures through the calculation of their far-field and near-field optical response. On the basis of simulations, the nanostructures were fabricated by e-beam lithography and thin film deposition. Special efforts were devoted to increasing the resolution and optimizing the reproducibility of critical parameters such as particle shape and interparticle gaps. Finally, far-field spectroscopy combined with two-photon induced luminescence (TPL) spectroscopy was used to probe the local optical response of the optimized architectures. We focused our attention on different families of structures: metal dimers, bar antennas, finite chains of nanoparticles and star-like particle arrangements. Particle dimers feature strong field enhancements in their sub-wavelength gap due to near-field coupling of their dipolar localized plasmon resonances. Based on the same physics, gap antennas, formed by two adjacent gold bars supporting multipolar resonances can efficiently couple to propagating light and concentrate it into tiny volumes. While finite particle chains were previously shown by other authors to be good candidates to guide light through subwavelength cross-sections, we show here that they can also be used as efficient nanolenses able to concentrate light at their extremity. Finally, the near-field distribution in star-like arrangements of gold nanoparticles exhibits a strong dependence with the incident field polarization which can be exploited for dynamical optical addressing of nano-objects. We have compared the far field spectroscopy of large ensembles of dimers and finite chains to TPL spectroscopy. Our main result is to show that TPL is preferentially sensitive to local fields and that it enables the assessment of spectroscopic features which cannot be resolved otherwise. In order to overcome the limitations of measurements on large ensembles a considerable effort was dedicated to mounting and optimizing an optical set-up enabling TPL measurement of single structures. Using the developed TPL micro-spectroscopy, spatially resolved spectral mode mapping on single resonant gap-antennas was achieved. As predicted by calculations, we were able to directly visualize at resonance the strongly enhanced TPL signal within the gap. Our results show how TPL scans can be directly compared with the convoluted distribution of the fourth power of the calculated local mode field. By monitoring the evolution with the incident wavelength of the TPL signal within the gap and at the antenna extremities we got further insight in the physical mechanism behind the buildup of the antenna’s resonance. Finally, TPL microscopy was used to probe the local fields under different orientations of the incident linear polarization near star-like arrangement of gold disks. It is shown that, unlike the scattering spectrum, the TPL distribution over the structure is found to depend drastically on the incident polarization state. Our study brings a significant contribution to the field of Plasmon optics by proposing novel geometries able to efficiently confine optical fields down to the nanometric scale, but also by providing deep insight into the use of TPL microspectroscopy to probe their local optical response. Our findings are foreseen to be important in applications such as enhanced spectroscopy, bio-sensing and enhanced light-matter interaction, where one needs to assess the actual field experienced by small amounts of matter.