In the framework of the EUVORAM project, we successfully created an overview of candidate materials for achieving metasurfaces for different extreme ultraviolet wavelengths (10 – 120 nm). Using numerical modeling, we created libraries linking the material and shape of nanostructures to their optical transmission properties allowing us to emulate most classical optics by drilling tiny holes in silicon membranes.
In collaboration with Harvard University, we fabricated the first transmissive lens (and overall optics) for extreme ultraviolet light. We demonstrated at TU Graz that this device works and focuses light to minuscule spot sizes - close to the physical (diffraction) limit. Extrapolating these proof-of-principle results to metalenses with higher numerical apertures (with larger diameter or shorter focal length) suggests that the technology can focus light below 100 nm.
To test such lenses for even smaller focusing and show that they also work for the shortest light pulses available today, with funding from the ERC, we built a state-of-the-art beamline for extreme ultraviolet light and attosecond experiments. In this beamline, we implemented a novel measurement technique, with which we demonstrated we can generate and manipulate pulses lasting less than 0.000 000 000 000 001 seconds.
We are now working to combine extreme spatial with extreme temporal resolution and develop methods to implement an attosecond microscope. With leaders in the field, we reviewed the most promising techniques with similar goals and their prospects for advancing science and technology, e.g. to understand the very start of energy flow from light to electrons in solids, to enhance communication and computation towards petahertz speeds, or to optimize the efficiency of light harvesting devices such as solar cells.
Furthermore, with support from the ERC, we exploited that attosecond physics and comb-based spectroscopy both rely on knowing the absolute phase of light pulses to create better (dual-comb) spectrometers in collaboration with the Coherent Sensing Laboratory at TU Graz, explored how metalenses can enhance photoacoustic imaging with the Optics of Nano and Quantum Materials Laboratory at KFU Graz, and, in collaboration with Harvard University, demonstrated how metasurfaces can design the shape of light in microcavities with unprecedented freedom.
