By: Dirk Wortman
Laser induced sub-100 nm structures offer vast potential benefits in photonics, biotechnology, tribological surface design and plasmonic applications. However the dynamics of their generation is not well understood. Research in this field requires high temporal and spatial resolution. In this paper, we report on our efforts on setting upand building an EUV-pump-probe microscope. The goal is the observation of femtosecond laser induced nanostructure formation with a spatial resolution of less than 100nm and a temporal resolution of less than 1ns.
A combination of a fs-laser and an EUV-microscope system provides a tool chain for controlled and reproducible production and analysis of nanostructures. Focused fs-laser radiation causes a local modification resulting in nanostructures of high precision and reproducibility. As exemplary structures, we use nanojets on thin gold films and periodic surface structures (ripples) on dielectrics. The unique interaction processes induced by fs-laser radiation open up new markets in laser material processing and are therefore a subject of current research. Microscopy using EUV-light is capable of detecting structures on a scale down to several tens of nanometers. An EUV-microscope, consisting of a plasma-source, collector, sample handling, zone plate and detector, has been constructed and built to achieve a high spatial and temporal resolution. By using a gated MCP as a detector we expect temporal and spatial resolutions < 1 ns and < 100 nm. The step for theoretical understanding the phenomena has been done by means of Molecular Dynamics (MD) simulations. The straightforward comparison of theory and experiment gives an opportunity to have a microscopic view at the nanostructure formation kinetics.