Analytical Study on Femtosecond Laser Ablation of Aluminum Nitride Ceramics

Abstract

This paper analytically investigates the ablation of aluminum nitride ceramics irradiated by femtosecond laser. There is now a growing interest in laser micromachining using pulses of ultrashort duration. Among its advantage is the possibility machining hard and brittle materials that can be easily damaged by conventional drilling and cutting procedures. Femtosecond laser micromachining of ceramics can produce nanoscale patterns due to the laser pulse duration shorter than the relaxation time of heat transport among phonons. Laser ceramics ablation possesses another feature, which includes the phase transition from solid to vapor without melting, the strong dependence of the thermophysical parameters and the volumetric absorption. The thermal process of femtosecond laser ceramic ablation is modeled by the heat conduction equation considering material evaporation. The predicted ablation depth per pulse is compared with the available experimental data and the effects of parameters on the ablated shape of aluminum nitride ceramics are also presented.