Regulation of molten pool in borosilicate glass welding with picosecond laser based on multifocal shaping

Abstract

Glass welding based on ultrafast laser is an effective method to achieve glass packaging. However, there are some problems in ultrafast laser glass welding, such as laser energy loss caused by the fact that the molten material generated by part of the laser energy cannot enter the gap to participate in welding, and microcracks. In this paper, borosilicate glass welding was conducted with high uniformity horizontal multi-focus based on an improved Gerchberg-Saxton (GS) algorithm proposed for the first time, which can effectively improve uniformity from 74 % to 99.8 %. By compressing the energy distribution of the beam propagation direction and increasing the energy distribution perpendicular to it, the formation of the molten pool can be regulated to prevent excessive longitudinal expansion of the laser action zone, resulting in a 75 % increase in weld width. Moreover, stress distribution can be reshaped to suppress the generation of microcracks. These advantages have a significant driving effect on the engineering application of this technology.