Interference ablation of nanogratings with different duty cycles on gold films

Nanogratings with different duty cycles are directly written on gold films using interference ablation. After exposing the gold film to the interference pattern of ultraviolet laser beams, gold film in the bright fringes will be melted and ablated, whereas much weaker ablation occurs in the dark fringes. The duty cycle of gold nanogratings can be controlled by adjusting the pulse energy and the exposure times, which can be explained by the temperature rise and cumulative effect of the laser–metal interactions. These results introduce additional parameters for the fine fabrication of metal nanogratings based on interference ablation at a large scale and low cost.