Self‐Aligned Laser‐Induced Periodic Surface Structures for Large‐Area Controllable Nanopatterning

Laser-induced periodic surface structures (LIPSS) have become an important avenue towards surface nanopatterning and certain device applications due to their subwavelength feature size and versatility with different materials. However, the uncontrollable non-uniformity in achievable nanostructures presents a limit towards its practical application. Here, a robust approach is proposed to obtain controllable nanostructures with long-range order based on a new insight into one of the electromagnetic origins of nonuniformity of LIPSS, namely a half-periodic mismatched optical enhancement (h-MOE) effect. The h-MOE effect originates from the interference enhancement of surface plasmon polaritons (SPPs) located between tips of every two adjacent ripples in laser scanning process. It is found that LIPSS can be self-aligned and highly controllable if the h-MOE effect is elaborately modulated through designed laser scanning strategies especially sequential scanning paths. The new laser nanopatterning approach based on h-MOE demonstrates controllable patterning ability to theoretically infinitely large-area super-straight gratings, orientation-controllable gratings, and half-periodic mismatched nanohole arrays.