Uniform periodic nano-patterning of metallic glass substrates via high-frequency nanosecond laser irradiation

Achieving high spatial uniformity in laser-induced periodic surface structures (LIPSS) has long remained elusive, as even femtosecond lasers, despite their nominally “cold” processing capability, cannot eliminate the stochastic defects that compromise long-range order. Here, we present a strategy that utilizes high-repetition-frequency nanosecond pulses, a regime traditionally deemed unsuitable for precision nano-patterning due to pronounced thermal dissipation, to fabricate one-dimensional (1D) LIPSS with uniform morphology on structurally homogeneous metallic glass (MG) substrates. This is achieved by exploiting strong inter-pulse correlation, which simultaneously moderates thermal fluctuations and sustains a coherent optical near-field to template deterministic pattern formation from stochastic seeds. Performing repeated scanning along the same single-line path transform these 1D patterns into regular two‑dimensional (2D) nanodot arrays. Finite-difference time-domain simulations reveal that a unified optical near-field interaction governs the entire structural evolution, from initial 1D ordering to subsequent 2D reconfiguration. The process preserves the MG substrate’s amorphous state and chemical composition while being inherently scalable. Uniform periodic nano-patterning with nanosecond lasers is challenging. Here, the authors demonstrate that by harnessing high-frequency pulses, such patterns can be fabricated on metallic glass substrates, exhibiting long-range spatial order.