Reproducible process regimes during glass welding by bursts of subpicosecond laser pulses.

Abstract

During welding of glass with ultrafast lasers, an irregular formation of weld seams was prevented by modulation of the average laser power and spatial beam shaping. The formation of individual molten volumes in regular intervals was achieved by means of power modulation, resulting in a predictable and reproducible weld seam with a regular structure. At constant average power, a homogeneous weld seam without a periodic signature was alternatively achieved by means of a shaped beam generating an elongated interaction volume and resulting in a continuous melting of the material. The influence of the two approaches, and their combination on the process dynamics, was analyzed by means of high-speed videos of the plasma emission and of the formation of the seams.