Study of thermal accumulation in glass welding using ultrafast laser at high repetition rate

Femtosecond laser welding of glass has numerous advantages, such as high mechanical resistance and high temperature tolerances without adding new material. In this context, an innovative way to join glass using a long focal lens of 100 mm has been developed. The advantages of using such a lens are clear: a drastic diminution of the thermal gradient and a slow thermal accumulation allowing crack free joining thanks to the larger focal volume, and a more robust process thanks to the long Rayleigh length. The study of the thermal accumulation process will be presented.