Prediction of crater shape in femtosecond laser ablation of dielectrics

This paper reports on a new model to investigate the femtosecond laser ablation of dielectrics by considering the time and space dependent optical properties of highly ionized dielectrics. A quantum treatment is employed to determine the free electron heating and the free electron relaxation time in the dense plasma. The proposed model greatly improves the prediction precision of ablation depth and can predict the crater shape of femtosecond laser ablation of dielectrics. The predicted ablation depths are in agreement with published experimental data for the example of barium aluminium borosilicate. Some interesting phenomena observed experimentally can be well explained by the proposed model.