Modification of Femtosecond Laser Absorption by Electron Beam Irradiation

Dielectric materials interact with ultra-fast lasers through various nonlinear absorption mechanisms, leading to ionization of the material.Specifically, quasi-free electrons are generated in the conduction band via multiphoton ionization (MPI) or tunneling ionization.When the density of these quasi-free electrons exceeds a critical threshold, ablation of the material occurs.In this work, the influence of extrinsically seeded electrons on the laser ablation threshold and the crater morphology on soda-lime glass for femtosecond laser single-shot experiments is investigated.For this, the laser was focused inside a modified scanning electron microscope, where the soda-lime glass samples were installed.Results show that irradiation with extrinsic electrons, provided by the SEM electron gun, can increase the ablation volume and decrease the ablation threshold.