Determination of irradiation parameters for laser-induced periodic surface structures

The spatial emergence of laser-induced periodic surface structures (LIPSS) on single-crystalline silicon, upon irradiation with linearly polarized picosecond laser pulses (wavelength λ = 1030 nm, pulse duration τ = 6.7 ps, pulse repetition frequency fp = 1 kHz) was studied theoretically and experimentally, under lateral displacement conditions. An experimental approach is presented for the determination of irradiation parameters of extended surface areas homogenously covered with LIPSS. The approach is based on accumulated fluence and consists of two steps, first the empirical determination of accumulated fluence domain boundaries and second the approximation of irradiation parameters. Such an approach is required for the application of LIPSS in the field of surface functionalization. The approach was successfully applied for structuring extended surface areas, which were homogenously covered with LIPSS. The areas, obtained by different irradiation parameter combinations, satisfying accumulated fluence boundary conditions, show the same type of LIPSS. This observation provides evidence, that the accumulated fluence has a decisive role in the spatial emergence of LIPSS. In the future, further experiments are required to verify the validity and boundaries of the approximations applied.