PROCESS FOR STRUCTURING SURFACES BY MEANS OF LASER RADIATION BY NEAR-FIELD OPTICAL INTENSIFICATION EFFECT

摘要

The invention relates to a process for structuring surfaces on extended areas by direct printing by using the laser ablation effect induced by the near-field intensification of the optical radiation. According to the invention, the process consists in manufacturing a micro-structural mask (1) by photopolymerization, then positioning the mask (1) on the surface of a material (2) to be structured and in irradiating it with a laser beam (3), by irradiation there being obtained micro-structures (4); the mask (1) comprises a support (5) and some focusing micro-optical elements (6), the structure of said elements (6) being formed of elements in the shape of cylinder or other structures with a geometry different from the spherical geometry, with micrometric and sub-micrometric dimensions, obtained from a transparent polymer material at the wavelength of the laser beam (3) used for the ablation; the material (2) to be processed may be the surface of a solid material or a thin film of a material deposited on a sub-layer (7), the mask (1) and material (2) to be processed are irradiated on a large surface with a single laser pulse or a laser beam (3) and, by the near-field intensification effect, the laser beam (3) is focused at the interface between the micro-optical elements (6) and the surface of the material (2), locally the optical irradiance exceeds the threshold of optical damage causing the laser ablation of the material (2), only at the surface, without affecting the mask (1); as a consequence of focusing the laser beam (3), the cylindrical micro-optical elements (6) generate line-shaped micro-structures (4) by the laser ablation, the layout thereof respecting the layout of the cylinders within the microstructured masks (1).