Optimal proportional relation between laser power and pulse number for the fabrication of surface-microstructured silicon

We experimentally demonstrate that, under the same laser fluence, there exists an optimal proportional relation between the laser power and pulse number for the fabrication of surface-microstructured silicon. During this fabrication process, the pulse number represents the interaction time between the laser and the silicon, which determines the depth of energy transferred into the inner part of the material, while the laser power determines the ablation and volatilization rate of the silicon. The proper combination of laser power and pulse number can ablate the material on the silicon surface effectively and have enough time to transfer the energy into the deep layer, which can produce microstructured silicon with a high spike. In addition, we compare the absorptance of samples etched by different combinations of laser power and pulse number; the corresponding results further prove the existence of an optimal proportional relation.