Prediction of particulate characteristics in an expanding laser plume

We present a mathematical model of particulate formation and dynamics in the laser ablation plume. This model is presented in a practical layout and applied to an example problem predicting the behavior of silicon, a material commonly used in the fabrication of microdevices. Additionally, we examine an intermediate intensity regime of laser ablation, in which there are multiple cooling mechanisms that can be considered important, but plume ionization is not significant. Results are discussed with an emphasis on pulsed laser ablation manufacturing processes, which often take place at atmospheric pressure. Important observations derived from this work are as follows: 1) The plume is quickly condensed and stopped in less than a microsecond in a distance of less than a millimeter at atmospheric pressure. 2) Particulates predicted by this model are on the order of 10Å in diameter, the majority of which condense back onto the target surface.