Method of forming periodic structures in thin films using interfering laser beams

摘要

The invention relates to the field of laser technology and provides for the direct formation methods of periodic structures in thin films, and can be used to produce periodic structures (arrays) for spectral and other optical devices, as well as shielding of electromagnetic field. This invention seeks to form periodic structures directly without using intermediate films (photoresist) and without using additional operations (placing photoresist, developing, chemical etching), and to control the formation of periodic structures with different shapes. Three or four, or six interfering laser beams get directed into the thin material film, in such a way that by interfering they would form a periodic laser radiation intensity distribution. At the high intensity zones of the interference pattern, the film material is ablated, while the remaining film material forms the periodic structure, which corresponds to the layout of low-intensity interference image. The shape of the formed periodic structures can be changed, by modifying the overall level of intensity of the interfering laser beams directed into the said film, by satisfying the condition the condition that the said total intensity at the maxima of the formed intensity distribution should be greater than the evaporation intensity threshold of the said film.