Abstract

Recently, light pulses generated by anti-Stokes stimulated Raman scattering of fourth harmonics of an Nd:YAG laser in H₂ have been successfully applied to laser ablation of Teflon films and fused quartz substrates.^1,2 This ablation technique is attractive for micro-fabrication of not only quartz but also other materials, which require the vacuum ultraviolet (VUV) laser for fabrication because the VUV laser system is simple. In the experiment with quartz, all of Stokes lines, anti-Stokes lines, and depleted pump from a Raman cell simultaneously irradiated to samples for laser ablation and it was found that the anti-Stokes pulses in the VUV region with small energy, which can not ablate the fused quartz substrate by itself, had important roles for fast fabrication without thermal distortion. However, mechanism of this process was not clear. In this works, we investigated the roles of the anti-Stokes pulses with low energy, based on measurements of absorption of the quartz substrate for fourth harmonics of an Nd:YAG laser.

© 1995 IEEE