研究目的
To optimize the microstructuring process of metallic molds using four-beam laser interference patterning to produce 'hole-like' periodic arrays with higher surface-area-to-volume ratios than the simpler 'line-like' grooves achieved by two-beam DLIP and to find a replacement for Ni molds to improve worker health and safety.
研究成果
Direct laser interference patterning is capable of producing Cr, Ni, and Cu molds for nanoimprinting systems. Using pulsed ps-laser radiation with optimized processing parameters, hole-like micropatterns with satisfactory quality and homogeneity were produced on those metal substrates. The laser induced microstructures on the three metals were replicated on PMMA foils using a hot embossing process. When Cr was used as mold material, the results showed a reliable reproduction of homogenously distributed hemispherical microlenses.
研究不足
The multi-pulse ablation process involves different effects such as melting, recrystallization, quenching, native oxide layer formation involving exothermic processes, defect generation and phase transformation, that can result in unexpected structure depth dependences with the number of pulses and fluence as well as modified mechanical properties of the final structured surface.