Laser manipulation of the size and shape of supported nanoparticles

Laser manipulation of the size and shape of metal nanoparticles prepared by self assembly of atoms on dielectric surfaces is discussed. The technique relies on the optical properties of the aggregates and the ability to remove atoms from their surfaces by laser induced thermal evaporation. A theoretical model which allows one to understand the basic mechanisms of the process is presented. Furthermore, experiments are reviewed which demonstrate that laser irradiation can be exploited for strong narrowing of initially broad size distributions yielding almost monodispersed samples and generation of aggregates with predetermined shape irrespective of their size. This makes possible preparation of very special surfaces with novel physical and chemical properties. Optical spectroscopy of the supported particles is demonstrated to be a very sensitive tool for characterization of such adsorbate/substrate systems, in particular for detection of laser induced modifications of the nanostructured surfaces. Finally, prospects for future experiments in this field and possible applications of the monodispersed systems are outlined. Received: 31 March 2000 / Accepted: 21 June 2000 / Published online: 7 March 2001