Versatile femtosecond laser interference patterning for high-precision nanostructuring of semiconductors and metal films

We present a direct fs laser interference patterning configuration, employing commercial or laser-fabricated diffractive optical elements, yielding a high-contrast, well defined excitation profile composed of periodic lines or spot arrays. High-precision patterns can be imprinted with the possibility of tuning the period from 5µm down to 650nm. Applied to crystalline silicon and germanium, amorphous nanostructures with sharp borders have been obtained. The obtained topography profiles demonstrate the presence of non-ablative matter reorganization processes. Applied to metal films, periodic nanostructures can be imprinted via local ablation. We present several mitigation strategies to address the problem of film delamination.