Picosecond Laser-Induced Bump Formation on Coated Glass for Smart Window Manufacturing

We report a study on the process of the formation of bubble-like structures on a coated glass surface using 50 ps laser pulses. The high-intensity interaction of laser radiation on the film–glass interface allowed us to develop a process for efficient glass bump formation. The high peak energy of the picosecond pulses has allowed us to merge the processes of coating evaporation and bubble growth into one. A parameter window was established within which efficient bump formation can be achieved. Well-defined spherical structures with a height up to 60 μm and a diameter up to 250 μm were obtained at pulse energy Epulse = 2.5 ÷ 4 μJ and laser fluence F = 2.5–0.41 J/cm2). The key aspects of the bump formation process were studied and are explained.