Here the wetting of ionic and nonionic surfactant solutions on a superhydrophobic interface, obtained by using a mixed inorganic-organic coating providing a fractal-like structure, has been investigated to define the role of adsorption at these interfaces. The presence of the amphiphilic molecules is effective in lowering the contact angle in a hydrophobic or still superhydrophobic range. Influencing the adsorption properties by acting on the surfactant type and concentration, the spreading of a drop on the surface can be controlled by amphiphiles confining its volume in a restricted space.

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We report optical second-harmonic generation ͑SHG͒ through modal phase matching in GaAs/ AlGaAs semiconductor waveguides. Using femtosecond pulses, both type-I and type-II SHG is demonstrated for fundamental wavelengths near 1.55 m.

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