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Summary: The central physical phenomenon described in this paper is the optical generation of surface plasmon polaritons within different kinds of nanostructures. It determines the local enhancement of the incident and scattered electromagnetic field by nearby molecules. The paper reviews different plasmonic devices whose design and spatial arrangement offer an optimal detection level of biomolecules when combined with Raman spectroscopy or hot electrons imaging. Recent results, obtained by the authors, demonstrated that it is possible to reach an analytical sensitivity in the attomolar concentration range, with an analytical specificity to solve complex peptide mixtures characterized by single point mutation in cancer detection experiments. In a different context, exploiting the adiabatic compression phenomenon, we have reported the possibility to generate both light and hot electrons sources in a localized area of few nanometers. Their energy control and accurate spatial localization allow the investigation of matter with unprecedented accuracy and richness of information. [ABSTRACT FROM AUTHOR]

Ga–Pb alloys with 15 at% Pb mean concentration have been prepared at the nanoscale by means of evaporation-condensation technique in ultra high vacuum conditions. Transmission electron microscope images indicate that at room temperature, the system is a two-components breath figure composed of liquid Ga nanodrops containing Pb nanocrystals. Some thermodynamic properties of this nano-alloy are investigated for different temperatures and particle sizes. The results obtained put in evidence a large modification of the Ga–Pb bulk phase diagram: a decrease of the melting temperatures of the two components as well as the ones of the miscibility gap. Changes in the microscopic structure of the system as a function of temperature have been investigated and a full wetting transition from a dry to a completely wet state has been put in evidence. [ABSTRACT FROM AUTHOR]

Solid/liquid two-components Ga–Pb structures in isolated nanometer sized particles have been produced and studied by electron microscopy. Production is based on the breath figure technique and we investigate the way the two components are distributed. We clearly identify two growth regimes associated with the two different ways a Pb atom incorporates into a Ga nanodrop. Using TEM and SEM, the shape and microstructure of the nanoparticles are studied and the results obtained are in good agreement with the proposed model. The experimental technique used appears to be appropriate to produce Pb nanocrystals in liquid Ga nano-containers. [ABSTRACT FROM AUTHOR]

In this work we use nonlinear optical properties of Ga nanoparticles monolayers of different average sizes embedded in dielectric matrices to investigate the liquid-solid phase transitions in these materials. Ga nanoparticles, formed by exploiting the partial wetting of liquid Ga over a SiOx surface are irradiated with fs laser pulses from a Ti:sapphire source. The resulting Second Harmonic (SH) generated in the reflection and transmission directions is measured along the phase transitions by cooling the sample from 320 K down to liquid nitrogen temperature. Hysteresis cycles are observed in the nonlinear transmission, which exhibit a strong amplification from the solid to liquid values as compared to the linear optical results. A simple model for SH generation, based on Mie scattering calculations which includes the effect of surface plasmon resonance provides a fair key for the interpretation of the observed effects. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]