Shaping metallic nanostructures and their optical properties through irradiation with short laser pulses

Summary form only given. We present experiments which demonstrate that post growth laser irradiation of metallic nanostructures, prepared by deposition of atoms onto substrate surfaces, can be used to narrow their size distributions considerably and to fabricate monodisperse particles with high number density on surfaces. For this purpose, the size dependence of the plasmon frequency, which dominates the optical absorption of the nanoparticles, is exploited for size selective laser evaporation of atoms from the cluster surfaces. If laser irradiation is not performed after growth but during preparation, particles with well defined and predetermined shape can be prepared by exploiting the pronounced shape dependence of the plasmon frequency. Both methods have been applied to Ag particles on quartz with radii between 0.5 and 5 nm. The drastic narrowing of their size distributions and the fabrication of well defined shapes is not only visible in scanning force microscopy images but is also reflected in the optical spectra. Tailoring the size and shape of the clusters implies tailoring the width and the maximum frequency of their optical absorption.