Micro- and sub-micromachining of type IIa single crystal diamond using a Ti:Sapphire femtosecond laser

A 200-fs pulsed Ti:Sapphire laser was used to micromachine Type IIa single crystal diamond. The effects of pulse energy and exposure time were investigated. Both blind and through holes were generated by trepanning and percussion modes. Trenches were produced by the direct-writing mode. Scanning electron and atomic force microscopy analysis revealed that the holes are in the range 0.65-100 mum and are free from taper. In addition, there was little recast layer around the holes. The damage threshold was approximately 4 J/cm(2), which is smaller than those obtained from other lasers. A two-temperature model was used to establish the electron temperatures and to predict the ablation depth per pulse. It is evident from this work that femtosecond lasers are capable of producing micron and sub-micron structures with very high precision.