Ultrafast Dynamics of Sub-wavelength Periodic Surface Structuring During Femtosecond Laser Processing of Dielectrics

A femtosecond laser pulse duration is shorter than many physical/chemical characteristic times, which makes it possible to control electron dynamics such as ionizations and electron densities. This study expermetally investigtes the effects of laser fluence on sub-wavelength periodic surface structuring based on ultrafast laser electron dynamics control. A quantum model for the sub-wavelength periodic surface structuring is also proposed, which considers both the wave properties in the photon particle-properties based plasma model for photon-electron interactions and transient localized changes of material properties. It shows that the laser fluence strongly affects the ablation crater shapes. The prediction of ablation crater shape and periodicity is in agreement with experimental data.