Photomechanical ablation of silicate glasses using femtosecond deep-UV laser pulses

The rapid advancement in solid-state femtosecond laser system development constantly increases the laser output power of systems. This opens a path for high harmonic generation, providing femtosecond deep-UV laser pulses that are efficient enough to initiate the ablation process in high bandgap material processing. Silicate glasses possess a broad transmission spectrum, high durability, and low price, making these materials an appealing choice in many fields, such as photonics, microfluidics, micro-optics, etc. Using deep-UV laser pulses instead of IR can provide more accurate results with precise depth control and significantly reduce unwanted damage to the surrounding area, offering a single-step, cost-effective, maskless approach for high-quality fabrication. In this paper, we present the ablation results of soda-lime and BK7 glasses using 300 fs 206 nm laser pulses generated by a regeneratively amplified commercially available Yb:KGW laser system. We demonstrate that the ablation process is photomechanical and thermal effects, as well as the stress impact, are minimized compared to the longer wavelengths. Furthermore, the surface roughness of the ablated microchannels falls within N3 grade (<100 nm) for most of the obtained parameter range, which proves the potential for the applicability of this one-step method for applications in optical systems.