Improved attenuation term of plasma model for femtosecond laser precision fabrication by online observation system

Femtosecond laser processing has been widely applied in fields such as mechanical manufacturing, optoelectronic devices, energy, military, and biomedical engineering. During femtosecond laser processing, the interaction mechanism between laser and material, and the simulation of manufacturing process are particularly important, which are related to the selection of laser parameters and the analysis of manufacturing mechanism. In the calculation process, a key parameter, the free electron lifetime, is usually simplified as a constant. For temporally shaped femtosecond laser processing, especially for femtosecond laser processing of fused silica, due to the existence of self-trapped excitons, the free electron density can no longer be regarded as a constant. In order to further improve the plasma model and make the femtosecond laser processing theory more accurate, an online observation system was used to probe the whole process of femtosecond laser double-pulse processing of fused silica in femtosecond time resolution. By fitting the observation results into the plasma model and improving the attenuation term, the precise plasma model can be established and the interaction mechanism between femtosecond laser and materials would be further clarified, which could promote the quality improvement of femtosecond laser processing.