Linear and nonlinear optical properties of gold nanoparticle-doped photonic crystal fiber.

We report on the production of air/silica photonic crystal fiber doped with gold nanoparticles. The stack-and-draw technique was used to combine a gold nanoparticles-doped silica core rod synthesized by the sol-gel route with capillaries drawn from commercially available silica tubes. The presence of nanoparticles in the core region was confirmed at the different steps of the process down to the fiber geometry, even after multiple drawings at ~2000 °C. Optical properties of the fiber were investigated and put in evidence the impact of gold nanoparticles on both linear and nonlinear transmission.

Laser-induced direct space-selective precipitation of CdS nanoparticles embedded in a transparent silica xerogel.

A simple method, suitable for direct space-selective precipitation of semiconducting nanoparticles inside a transparent silica xerogel, is presented. The porous silica monoliths, prepared by the sol-gel method, are first loaded with specific CdS precursors. Then, the samples can be irradiated using either a femtosecond laser to generate the nanoparticles inside the deep volume of the silica matrix or a continuous visible laser to yield a nanocrystal growth under the surface. The resulting CdS nanoparticles are characterized using absorption and Raman spectroscopies, x-ray diffraction analysis and transmission electron microscopy.