Study on a fabrication mechanism of the fused silica nano-sized surface structure by using the copper deposited and femtosecond laser light irradiation

Abstract

Femtosecond lasers can be used for forming a nano-sized periodic structure on the surface of fused silica. However, the processing control range is narrow and unstable due to the nonlinearity of the multiphoton absorption process. By coating the surface with a thin metallic film, we found that the periodic structure can be formed easily below the ordinary ablation threshold for fused silica. However, the periodic structure processing mechanism was not understood. We proved that the metallic nanosized particles on the fused silica contributed to the nano-sized structure formation, and confirmed that the nano-sized structure could be formed even with laser processing of only one pulse. Furthermore, the depth of the nano-sized periodic structure depends on the volume of the metallic nano-sized particles.