Local Laser Oxidation of Thin Metal Films: Ultra-resolution in Theory and in Practice

Laser-induced oxidation on thin metallic films with following selective etching is a powerful method for micropatterning of different structures like photomasks, diffractive optical elements etc.Nowadays the most interesting question is how small could be structures produced by this technology, what are theoretical limitations and where is a practical limit for that? Under this research will be shown that Arrhenius dependence of oxidation speed from temperature raises this limit on some orders of magnitude higher then the resolution of thermal image. Corresponding calculation will be done and will be verified experimentally. From the other hand rgimes of laser irradiation (power density, time of irradiation etc) as well as rgimes of selective etching (type of etchant and its concentration), material of thin film and its thickness have also big influence on the final results. Experimental and practical results for fabrication of many specific components and devices as different diffraction lenses, diffraction attenuators, synthesized holograms will be demonstrated.