Optical micro-structuring of metal films on the surface of dielectric materials: prospects of shaping by non-diffracting optical beams

The technique of optical micro-structuring of metal films based on processes of metal atoms adsorption on the surface of crystalline substrate and simultaneous controllable photo-stimulated desorption of atoms by non-uniform laser beam illumination is presented. The experiments were performed for sodium atom deposition on a sapphire substrate. The sapphire substrate was illuminated through a commercial linear mire with a pitch of 10 $\mu$m by a 440 nm laser beam with 1W/cm$^{2}$ intensity. This provides the nonuniform spatial distribution of the illumination intensity over the sapphire surface and optical control of sodium atom deposition on the sapphire substrate, preventing the nucleation and growth of the granular film in the illuminated areas. Experiments showed that the mire pattern was well reproduced in the sodium deposits, thus creating the microstructured metallic film with few tens nm thickness. The novel suggestion to use nondi racting optical beams for high contrast microstructuring of surface metal film is presented.