Advances in the development of ultrafast lasers have opened up new applications and possibilities for high-precision material processing that cannot be realised with traditional laser systems. For example, femtosecond Ti: Sapphire lasers have established as excellent and universal tools for the microstructuring of metals using techniques such as direct laser writing or direct laser interference patterning (DLIP). However, it is still unclear to what extent this laser is feasible for the microstructuring of polymer surfaces.

The aim of this work was to achieve fs and ps-DLIP structuring of commercial transparent polymers foils (polycarbonate, polyetheretheretherketone and polyethylene terephthalate) using a femtosecond-pulsed laser (CARBIDE-CB3-40W, Light Conversion, Lithuania) with a variable pulse duration in the range of 0.266–10 ps and an emitting wavelength of 1030 nm. The multiphotonic structuring mechanisms governing these systems were studied and the topographical, physicochemical and chemical modifications that occur after structuring of the material were analyzed.

Patterning of the transparent polymer films by DLIP could be achieved for all the cases but creating a variety of structures. The characterization techniques (ATR-FTIR, Raman, and XPS) used showed that the polymer surface was slightly modified after the laser process at the nanometre level (2-12 nm) in the central zone of the laser pulse (where the laser fluence is at its maximum), however, the bulk integrity of the polymer remained intact.