Nanosecond Laser Processing of Soda-Lime Glass

Glass is an important engineering material for a number of different applications. Over the last years demand on fast and high-quality processing of glass has increased. Although femtosecond or picosecond laser systems offer excellent processing quality, less complex nanosecond laser systems are more stable and widely used for industrial applications and can offer lower processing costs. In this work, we investigated helical drilling of holes in thick soda-lime glass sheets initiating the process from the backside of a sample. Nanosecond laser pulses with wavelength of 1064 nm or 532 nm, tightly focused in the bulk of transparent material, were absorbed due to avalanche ionization. During the 30 ns laser pulse interaction with glass, micro-cracks were induced and drilling debris was ejected through the etched channel. This approach allowed us to drill the high aspect-ratio taper-less holes in the 4 mm thick soda lime glass with maximum throughput of 1.2 s per hole. Nanosecond Q-switched diode-pumped solid state (DPSS) laser offered low cost and fine quality drilling at high processing speed.