The Mechanics And Application During Femtosecond Laser And Solid Material Interaction

An intense femtosecond laser pulse can provide an electric field strength which exceeds the electric field force of valance electrons that holds the electrons to their ionic cores. which make great changes with electron systerm of molecule and atom. In the process of femtosecond laser micromachining different solid materials such as dielectric, semiconductor, metal etc, the way of materials absorb pulse energy and the way of heat transfer vary due to the different physical structure of materials. Which cause a different melting mode. This thesis is focused on the mechanics of how the solid absorb energy of laser pulse and how the heat transfer within the material, what's more, some experiment in femtosecond laser micromachining nickel alloy and silicon is in research.In theory, the process of laser micromachining is divided into a heat process and none-heat process, and the femtosecond laser micromachining is seemed to be a none-heat process. Aferthat, the two temperature modal (TTM) is used to simulate the non-equilibrium temperature distribute of electronics and lattice during femtosecond laser micromachining metals.In experiment, we use 800nm, 120fs femtosecond laser micromachining nickel alloy CMSX-4 under different conditions, such as in air and in vacuum background, the number of laser pulse vary as N=10, N=100, N=1000, then the size of the hole is obtained and the damage threshold can derive by gauss equation. What's more, a silicon slice was fabricated by femtosecond laser under the background of low consistency sulfuric acid liquor, the result show a explicit change of microstructure in silicon surface and the fluorescence character of silicon is improved, Thus give a new and simple method to increase the fluorescence property of silicon.