Effect of Porosity and Pore Size of a Silicon Target on the Laser Ablation Threshold

Laser ablation of a porous silicon target irradiated by ultrashort IR laser pulses in an air environment is simulated using the molecular dynamic approach. The number of ablated atoms is calculated for targets with different porosity and pore size. It is found that a porous silicon target with 1 nm pore size is ablated more efficiently at low laser pulse fluences. It is shown that an increase in the target porosity leads to a decrease in the ablation threshold: with a change in porosity from 10 to 50%, the laser ablation threshold decreases by more than 1.5 times. The obtained results can be applied to optimize the regimes of laser ablation synthesis of nanoparticles using nanostructured porous silicon targets.