DLIP: the tool for periodic-precise nanostructure fabrication (Invited Paper)

Direct Laser Interference Patterning (DLIP) allows the fabrication of multiple structures with one single shot thanks to the periodic intensity distribution due to the interference of two or more laser beams. A great richness of periodic patterns can be achieved depending only on the laser irradiation conditions, being completely independent of the irradiated material. We have developed a versatile DLIP configuration in which, by changing two key elements, a diffraction grating and a microscope objective, fringe patterns with different periodicities can be achieved. We employ an Ti:Sapphire laser (120 fs, 800 nm) to process semiconductors as silicon and germanium to produce high-precision amorphous fringes with distinct topographies depending on the periodicity. Furthermore, the dynamic material phase transformation is studied with fs pump-probe reflectivity experiments, revealing the different stages of the process (electronic excitation, non-thermal melting and solidification). Fs-microscopy measurements in a diffraction configuration allow to monitor the dynamics of the topographic modification, being a result of molten material reorganization processes, such as Marangoni flow and surface capillary waves.