Simulation of ultrashort pulse laser drilling of glass considering heat accumulation.

In accordance with the increasing demand for high-speed processing, the repetition rate of ultrashort pulse lasers has continued to increase. With the development of these lasers, there is a growing demand for the prediction of shapes processed at high repetition rates. However, the prediction of these shapes is a major challenge, because of the difficulty associated with the estimation of heat accumulation. In this study, we developed a simulation of ultrashort laser drilling in glass including heat accumulation calculation between pulses. In this simulation model, temperature is considered as an additional criterion of material removal, thus, the dependency of the repetition rate can be estimated. Two model parameters of laser absorption at high temperatures are investigated and determined by experiments under high environmental temperatures. Using the simulation model, high shape-prediction accuracy at high repetition rates was achieved and validated by comparison with experiments. This study may contribute to broadening the applications of high-repetition-rate ultrashort pulse lasers.