Laser-induced patterning of silver thin films using interference effects

Submicron patterning of the spatial arrangement of spherical silver nanoparticles on a substrate is reported. The patterned samples were obtained by irradiating a thin silver film in the quasipercolated state with short laser pulses. Light reached the sample through a slit on a highly reflecting silicon mask placed parallel to the surface of the sample and was reflected between the sample and the inner face of the mask. The incident and reflected light interfered on the sample’s surface creating a complicated pattern of thin lines along which spherical-shaped silver nano-particles are concentrated. We provide a simple model to explain the observed patterns and briefly discuss how could one control the shape and thickness of the patterned lines of nanoparticles.