Enhancement of laser-induced plasma-assisted ablation of glass substrate via interacting spatial double laser pulse irradiation

Glass is a brittle and hard material with good chemical properties. Its wideband optical transparency makes it a challenge to apply nanosecond lasers to process glass. This paper proposes interacting spatial double laser pulse irradiation to enhance laser-induced plasma-assisted ablation (LIPAA). Two split laser beams simultaneously irradiate on metal target at an adjustable horizontal gap (center distance between two laser pulses). This gap has a significant impact on laser-processed glass quality. The optimized laser fluence for the LIPAA is obtained. The width and volume can be increased up to 1.5 and 1.7 times by this novel approach. The enhancement outcome is attributed to the interaction between two plasmas induced by double laser pulse irradiation. The resulting plasma becomes larger and stronger, which strongly interacts with glass backside surface and creates a larger ablation crater. This method has great potentials to process other transparent materials, such as sapphire, diamond, and crystal by laser micromachining.