Crack-Free Laser Processing Of Glass Substrate And Its Mechanisms

Laser-induced-plasma-assisted ablation (LIPAA) for crack-free laser processing of glass substrate is investigated. Different from laser breakdown at high laser fluence, a pulsed green laser is used to achieve the glass processing in air at much lower laser fluence. Laser beam goes through the substrate first and then irradiates on a solid target behind. For laser fluence above target ablation threshold, plasma generated from target ablation flies forward at a high speed. At a small target-to-substrate distance, there are strong interactions among laser light, target plasma and glass substrate at its rear side surface. With the target materials deposition on the glass surface or even doping into the glass substrate, light absorption characteristic at the rear side surface is modified. The laser processing result is closely related to target-to-substrate distance, laser scanning speed and its repetition rate. Color marking, glass metallization and structuring can be achieved with the fine tune of the laser processing parameters.