An investigation on the laser ablative shaping (LAS) of the quartz glass has been made experimentally. F2 laser was used as the laser light source for efficient ablation of quartz material. The output beam of F2 laser was focused on to the surface of quartz plate. The ablation rate was about 10 micron m/pulse at the irradiation fluence of 2 J/cm². A uniform ablation of quartz plate has been demonstrated using F2 laser. The waveform of incident and transmitted laser light was measured by high speed photo-tubes to observe the time dependence of the absorption. The measured waveform indicates that the absorption was small at the leading edge of the laser pulse, and a strong absorption was induced at the end of laser pulse due to the excited state absorption. These phenomena are quite similar to both in F2 and ArF laser light. We have developed a simple model in which the instantaneous absorption is proportional to the absorbed energy prior to the moment. The calculated absorption was in good agreement with the measured wave- form. The change of transmittance in UV and VUV region was measured after the irradiation of F2 laser for samples of different concentrations of impurities.

Date Published: 6 November 2000
PDF: 4 pages
Proc. SPIE 4088, First International Symposium on Laser Precision Microfabrication, (6 November 2000); doi: 10.1117/12.405729

Published in SPIE Proceedings Vol. 4088:
First International Symposium on Laser Precision Microfabrication
Isamu Miyamoto; Koji Sugioka; Thomas W. Sigmon, Editor(s)