Experimental and numerical investigation of CO2 laser ablation of fused silica with sub-microsecond pulses

The CO2 laser material interaction is commonly used for thermal treatments and processing of fused silica glasses. As the laser pulse duration decreases down to a few tens of microseconds, the heat-affected depth in the material decreases up to the point where it has the same magnitude as the laser radiation penetration depth, which is an interesting operating point for applications that require minimal heat-affected zone. In this work, we explore the effects of CO2 laser pulses in the range of 100 μs to a few milliseconds on the laser ablation of polished fused silica surfaces, based on experiments and numerical simulations. We particularly study the evolution of surface profile as a function of the number of applied pulses. The results suggest that the ablation depth can be accurately controlled from a few hundreds of nanometers to a few tens of micrometers by adjusting the combination of the number of applied pulses and pulse duration.