A molecular dynamics model for studying the effect of picosecond laser pulse overlap on silicon carbide ablation processing

Abstract

A high-precision molecular dynamic model of single pulse picosecond laser ablation of silicon carbide crystal is constructed by introducing one thousandth laser focal spot diameter and adjusting the appropriate coupling coefficient, and the correlation between the nanoscale simulation and microscale experimental reproduction is achieved. After that, in order to establish a precise correlation between scanning speed and the effective pulse number, a laser intensity correction factor for charactering the attenuation of Gaussian light over distance is introduced. When the scanning speed is 300.00, 200.00 and 100.00 mm/s, the intensity-corrected pulse overlap rate is 106 %, 156 % and 230 %, which is converted to an effective pulse number of 1.06, 1.56 and 2.30, respectively. The calculated effective pulse number is used as an input to the molecular dynamic model. The high-precision molecular dynamics model with the input of effective pulse number is then used to simulate the effects of pulse overlap rate and laser fluence on the ablation results. By comparing the calculated ablation widths with the experimental detection results, the accuracy of the model study pulse overlap rate and laser fluence ablation results are both proved to be higher than 95 %, and the average error between the experimental and simulation methods are both proved to be less than 1 %.