Lately composite materials containing metal nanoparticules have found an increasing number of applications in different fields of science and technology. In particular glasses containing metallic nanoparticules are of great interest for photonics because of their unique linear and nonlinear optical properties, which are determined by surface plasma oscillations of the metal clusters. The surface plasmon resonance depends strongly on shape, distribution and concentration of the nanoparticules, as well as on the surrounding dielectric matrix. This offers the opportunity to manufacture very promising new nonlinear materials, nanodevices and optical elements by manipulation of the nanostructural properties of the composite medium. Recently, laser-based techniques leading to modifications of shape and size of the metal clusters have increasingly become of great interest and proved to provide a very powerful and flexible tool to control and optimize the linear and nonlinear optical properties of such materials. More generally, this technique allows the engineering of the optical properties of the material via gaining control over the spatial distribution of nanoparticules in the glass matrix. The possibility to 3D spatially structure the linear and non-linear properties of various materials leads thus to consider femtosecond laser as a fantastic tool. However, a deeper understanding of the light-matter interaction, with emphasis on multiphotons processes, is profoundly needed for the development of new optical devices based on nanoparticules mastering. This proposal is thus dedicated to 1/ to understand the processes of the formation of metallic nanostructures in glassy media and 2/ to manipulate, to master the nanocluster shape and mostly distribution within the dielectric matrix. This will allow structuring the non-linear properties in the dielectric matrix on demand.