Thermal model for nanosecond laser ablation Al2O3 considering temperature dependence

Abstract

This paper presented a thermal model based on heat-conduction and vaporization to predict the ablation profile by nanosecond pulsed laser in Al2O3. The temperature distribution is estimated by heat transfer in the laser irradiated zone, considering temperature dependence of material properties. The ablation profile was analyzed and predicted, which has considered the laser spatial and time-distribution and the effective number of laser pulses within the irradiated area. To validate the accuracy of thermal model proposed, micro-channel experiment has been performed. The morphology and profile of micro-channel was measured by Scanning electron microscope (SEM) and an 3D microscope. The difference in microstructure of SEM can be attributed to the laser-material interaction associated with the temperature distribution. Good agreement between calculated depth and width of microchannel and that of experimentally measured and its dependence on incident laser parameters validated theoretical model. Whereas, the degree of error marginally increases at high laser power fluences due to the model proposed ignored the optical properties. The errors of side-wall of micro-channel can be attributed to the effect of multi-reflection and plasma on the channel side-wall.