Adjustments of dielectrics craters and their surfaces by ultrafast laser pulse train based on localized electron dynamics control

A quantum model with the consideration of laser wave-particle duality based on the plasma model is employed for the femtosecond laser pulse train processing of fused silica. Effects of the key pulse train parameters, such as the pulse separation time and the number of pulses per train on the distributions of free electron are discussed. The calculations show that the spatial/temporal distributions of free electron can be adjusted by transient localized electron dynamics control using femtosecond laser pulse train design; the results are ablation shapes of craters and subwavelength ripples. It is also found that the first pulse separation time (Δt1) can be used for rough adjustments of ablated structures, while the second pulse separation time (Δt2) can be used for the fine tuning of ablated structures, especially the shapes of craters.