A new setup for the study of adsorption/desorption processes and nanoparticles formation in porous alumina

We present a setup devoted to the study of adsorption and desorption processes of alkali atoms after deposition on a 300 nm thick porous alumina substrate in an Ultra High Vacuum chamber. Rubidium atoms, delivered by a dispenser source, enter the 20-30 nm diameter pores, diffuse in and stick to their walls. A 1 W power laser is used in order to induce detachment and take the atoms back in the vapor phase in a very tight confinement region. The desorbed atoms coming out the sample can be monitored via both a resonant optical detection and an electronic amplifier after ionization. The desorbing laser is also able to promote the formation of Rubidium nanoparticles, as the high Rb vapor density in the pores favors aggregation around nucleation point defects. In this way, the apparatus allows for the study of the fundamental processes related to atom – surface interactions in presence of light as well as of several promising application to nanomaterials.