Formation of strong light-trapping nano- and microscale structures on a spherical metal surface by femtosecond laser filament

Abstract

Nano- and microscale structures on a material surface formed by femtosecond laser processing have greatly changed optical characteristics, wettability, as well as other properties of the material. In this work, we report the formation of nano- and microscale structures on a spherical Al surface with femtosecond laser filament, and find that the filament-processed surface has a strong light-trapping ability from UV to IR (0.2–2.5 μm). Our result demonstrates that this method can be used to process a spherical surface without the complexity of a 4-axis sample control, and in principle, it is applicable to any non-planar sample.