Femtosecond Laser Micromachining of Si-on-SiO₂ for Photonic Band Gap Crystal Fabrication

Abstract

Femtosecond laser pulses at 387 nm were used to machine Si-on-SiO 2 substrates for photonic band gap crystals. With 387 nm ultrashort near-UV pulses, we obtained holes as small as 160 nm, which is smaller than one half of the laser wavelength with only conventional optics. Moreover, a pitch size of 420 nm is also obtained in Si-on-SiO 2 , which meets the spacing requirement for today's telecommunication frequency -1550 nm. Ultrafast laser micromachining is fast and versatile, thus it is a powerful tool for in-situ microstructure operations such as nanostructuring, repairing, and production industrial applications.