We developed a longitudinally excited CO₂ laser that produces a short laser pulse. The laser was very simple and consisted of a 45-cm-long alumina ceramic pipe with an inner diameter of 9 mm, a pulse power supply, a step-up transformer, a storage capacitance, and a spark-gap switch. The laser pulse had a spike pulse and a pulse tail. The energy of the pulse tail was controlled by adjusting medium gas. Using three types of CO₂ laser pulse with the same spike-pulse energy and the different pulse-tail energy, the characteristics of the hole drilling of synthetic silica glass was investigated. Higher pulse-tail energy gave deeper ablation depth. In the short laser pulse with the spike-pulse energy of 1.2 mJ, the spike pulse width of 162 ns, the pulse-tail energy of 24.6 mJ, and the pulse-tail length of 29.6 μs, 1000 shots irradiation produced the ablation depth of 988 μm. In the hole drilling of synthetic silica glass by the CO₂ laser, a crack-free process was realized.

Date Published: 4 March 2015
PDF: 6 pages
Proc. SPIE 9350, Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XX, 93501E (4 March 2015); doi: 10.1117/12.2077924

Published in SPIE Proceedings Vol. 9350:
Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XX
Stephan Roth; Yoshiki Nakata; Beat Neuenschwander; Xianfan Xu, Editor(s)