Experimental and Theoretical Investigation of CO2 Laser Drilling of Fused Silica

Single and multiple laser pulse hole drilling in fused silica have been carried out using a CO 2 laser system operating at 10.6 m. Laser pulse duration, pulse energy and number of pulses impinging on the silica plate have been measured in-situ for drilled holes. Hole depths, diameter and volume have been measured using a fluorescent confocal microscope and the results are compared against the predictions of a numerical model. This model considers surface evaporation as the main material removal mechanism. For the case of single pulse drilling, the depth and volume of the drilled holes are predicted accurately and the discrepancy between the model and experiments are observed to be less than 10%.