Sub-wavelength pattern generation by laser direct writing via repeated irradiation

A simple technique is presented allowing the fabrication of high density periodic patterns via direct laser ablation. Applying fluence control for reducing the ablated feature sizes combined with lateral translation of an interference pattern between two (or more) irradiation cycles, sub-wavelength period patterns (< 200 nm) are created. Variation of the amount and direction of translation and the applied intensities during subsequent irradiation steps leads to variable pattern design as demonstrated for polymeric and silicon samples.