A femtosecond laser beam focused inside fused silica and other glasses can modify the refractive index of the glass. Chemical etching and atomic-force microscope studies show that the modified region can have a sharp-tipped cone-shaped structure with a tip diameter as small as 100 nm. Placing the structure near the bottom surface of a silica glass sample and applying a selective chemical etch to the bottom surface produces clean, circular, submicrometer-diameter holes. Holes spaced as close to one another as 1.4 μm are demonstrated.
© 2003 Optical Society of America
R. S. Taylor, C. Hnatovsky, E. Simova, D. M. Rayner, V. R. Bhardwaj, and P. B. Corkum, "Femtosecond laser fabrication of nanostructures in silica glass," Opt. Lett. 28, 1043-1045 (2003)