Numerical Modeling of Excimer Laser Curved Surface Ablation

Abstract

Laser ablation has been widely used in the fabrication of miniature parts. The technique is also used in the fabrication of micro lens or micro-curved surfaces which find potential applications in various optical, bio- medical, electronics, MEMS applications. This work presents development of two novel techniques employing profile path approach and beam profile approach for fabrication of curved surfaces by Excimer laser ablation. Laser ablation is widely used for their fabrication on account of its exceptional capabilities. In this paper, a two-dimensional finite element model is developed to predict temperature distribution and ablation depth in a laser ablation process. A correlation between the incident laser fluence and depth of the ablated crater is analytically gener-ated based on the FEM model. Using this correlation, the profiles of the surface ablated using profile path and beam path approach is predicted based on a finite element model incorporating the pulse variation in profile path approach and spatial variation of intensity of the incident beam in the beam path approach. Modeling of various profiles like flat, circular, Gaussian and other is also presented. An attempt has been made to validate the proposed techniques experimentally.