Nanoparticle formation in nanoporous structures and applications

In this paper, we present a series of experiments where alkali atoms have been implanted in nanoporous structures, in such a way that, by light, we can induce and control the formation and the destruction of alkali nanoparticles, having slightly different average sizes and shapes: the key role is given by photo-desorption processes (the so called light induced atom desorption and surface plasmon induced desorption effects). The porous materials are both commercial glasses and “home made” thin films of alumina. While the borosilicates, filled by Rubidium, Cesium, Potassium or Sodium, have been studied in dedicated sealed absorption cells, porous alumina samples have been investigated in a Ultra High Vacuum chamber. As an application, the illumination of a porous sample by a structured laser beam, as generated by a conical lens, allows for the preparation of ordered nanoparticle patterns on micrometric scale resolution: these new systems are promising in the growing field of all-optical photonic devices.