Comparison of glass processing using high repetition femtosecond (800nm) and UV (255nm) nanosecond pulsed lasers

Laser processing of glass is of significant commercial interest for microfabrication of "lab-on-a-chip" microfluidic devices. High repetition rate pulsed lasers have been investigated and provide adequate processing speeds but suffer from the inherent risk of laser-induced microcracking and other collateral damage induced in the glass. In this paper we present a comparative study between nanosecond deep UV (255nm) frequency doubled copper laser and femtosecond Ti:Sapphire (800nm) regenerative amplifier laser machining of borosilicate glass. Microchannel scribing and high aspect ratio hole drilling is demonstrated in thick glass using direct writing and mask projection techniques. The resulting material structure geometries have been examined using SEM microscopy and white light interferometry. The feasibility of glass laser machining and the significance of each laser type for this application are discussed.