Hybrid laser processing of hard materials

Summary form only given. Recently, much attention has been paid to pulsed laser ablation as a powerful tool for micromachining of materials. Nanosecond (ns) UV lasers are usually used for this purpose. Such lasers, however, often induce severe damage and cracks in hard materials possessing wide band-gap and large lattice energy, e.g., fused silica. Thus, lasers of either a VUV wavelength or a sub-picosecond pulse are applied, while such lasers have many difficulties for practical use. On the other hand, hybrid laser processing, in which interaction of a ns laser beam and another medium on the material surface leads to effective ablation, opens new avenues for industrial application. For example, simultaneous irradiation of the VUV laser beam of small pulse energy with the UV laser beam performs accurate ablation of the hard materials (VUV-UV multiwavelength excitation process). In the meanwhile, laser-induced plasma effectively assists high-quality ablation of transparent materials to the laser beam, resulting in submicron grating fabrication and high-speed hole drilling of glass materials (laser-induced plasma-assisted ablation (LIPAA)).