Laser microfabrication of transparent hard materials and signal diagnostics

Laser-induced-plasma-assisted ablation (LIPAA) for glass microfabrication is investigated. A short pulse laser is applied to ablate a glass substrate. With proper control of laser parameters, surface microprocessing of the glass can be achieved. The laser beam goes through the substrate first and then irradiates a target beneath. For laser fluences above ablation threshold of the target, the target plasma flies toward the substrate at a high speed. At a short target-to-substrate distance, there are strong interactions among the target plasma, incident laser beam and glass substrate at its backside surface to induce ablation of the glass. A ultrafast phototube and optical emission spectrum analyzer are applied to study the dynamic interaction. From the signal diagnostics and analyses, laser-induced glass microfabrication can be monitored in real time.