Laser-Based Fabrication of Nanofoam inside a Hollow Capillary

Abstract

Highly porous nanofoam can be fabricated via multiphoton ablation of a material by raster-scanning femtosecond laser pulses over the material surface. Here, we show the fabrication of nanofoam on the inside surface of a hollow silica capillary that has an inner and outer diameter of 640 and 700 ?m respectively. A thin layer of nanofoam was fabricated over ~70% of the inner surface of the capillary. Ray-tracing simulations were used to determine the positional corrections required to account for refraction on the curved surface and also to explain the inability to fabricate nanofoam on the side walls of the capillary.