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.

Ultrafast Laser Direct Writing in Glass: Thermal Accumulation Engineering and Applications

“…[ 163 ] Bessel‐like beams are reported to improve the regularity and homogeneity of the seam structure and lead to an enhancement in the shear joining strength. [ 162,164 ] Substance mixing has been identified by the Raman spectrum and element distribution analyses, confirming the laser induced bonding. Recently, welding between glasses, glass‐other substrates such as silicon, ceramics, and even semiconductor–metal has also been demonstrated.…”

“…[ 160 ] To scale up the throughput of laser welding, bursts of ultrafast laser pulses are adopted and a high breaking resistance that can be up to 96% of the bulk material is achieved. [ 161,162 ] Using a long focal length lens integrated in a scanner head, a lower peak temperature increase with smooth temperature dynamic is achievable and reduces the residual stress in the welding seams, and the welding scanning speed is up to 1000 mm s −1 . [ 163 ] Bessel‐like beams are reported to improve the regularity and homogeneity of the seam structure and lead to an enhancement in the shear joining strength.…”