We report on the observation of a strong coupling between a surface plasmon and an exciton. Reflectometry experiments are performed on an organic semiconductor, namely, cyanide dye J aggregates, deposited on a silver film. The dispersion lines present an anticrossing that is the signature of a strong plasmon-exciton coupling. Mixed states are formed in a similar way as microcavities polaritons. The Rabi splitting characteristic of this coupling reaches 180 meV at room temperature. The emission of the low energy plasmon-exciton mixed state has been observed and is largely shifted from the uncoupled emission.

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Gadolinium oxide films, prepared by the sol-gel process, present waveguiding properties. Their structures were studied by waveguide Raman spectroscopy (WRS) and confirmed using transmission electron microscopy (TEM). The structural evolution of the layers with annealing temperatures from 650 up to 900 • C was investigated. The WRS results and TEM observations were correlated and revealed that crystallization started at 650 • C into the cubic phase. The mean diameter of the crystallites dispersed in the amorphous phase is around 5 nm at this temperature. The film is totally crystallized into the cubic phase at 700 • C. The monoclinic phase simultaneously appears at 800 • C and both phases still co-exist after heat treatment at 900 • C. The films present a heterogeneous structure at 900 • C with grain sizes varying from 5 up to 50 nm and as consequence their waveguiding properties strongly decrease.

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Survival of bacteria (Rhizobium, Agrobacterium, and Arthrobacter spp.), fungal spores (Penicillium sp.), and yeasts (Saccharomyces sp.) was studied in relation to water activity (aw) and the presence of nutritive solutes.

The fabrication of microcavities by a sol–gel process and their optical properties are described. The cavities are constituted of an Eu3+-doped SiO2 active layer inserted between two Bragg mirrors, fabricated by stacking alternatiely undoped TiO2 and SiO2 sol–gel thin films. Eu3+ luminescence modification due to the cavity effect, intensity enhancement and modification of the line shape has been observed, and shows a cavity quality factor of 1200. The reflectivity factor of the associated Bragg mirrors reaches 99.8% for seven alternate SiO2/TiO2 layers.

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