Extreme nm-level precision in laser structuring with ultrafast non-diffractive beams

The recent progress in ultrafast laser material processing techniques paved the way towards reaching nm-scale feature size in material structuring, coming close to atomic precision. With a demonstrated capability in the 10 nm range, this implies a laser scribing performance of almost λ/100, a highly super-resolved laser structuring process. A nm feature size intrinsically relies on the involvement of local near-field optical activity during the ablation process, occurring both on surfaces and in the bulk, implying equally a nanoscale material reaction that triggers evanescent waves when irradiated by far field optical beams. Such resolutions and feature sizes are prone to open up new breakthrough developments in laser processing, notably in the definition and prototyping of new scale-dependent materials and functions. Adding high aspect ratios to nm size structural features by employing non-diffractive beams creates a new processing flexibility that can be exploited in innovative functional design of materials. We discuss current progress in the use of non-diffractive ultrafast laser beams matching nm scale structuring and high aspect ratios and emphasize some of the challenges and the opportunities of a unique laser processing technique on the roadmap towards atomic resolution.