Advancements in Extreme Ultraviolet Metaoptics

This lecture discusses the innovative use of extreme ultraviolet (EUV) light in attosecond physics and semiconductor lithography. The instructor presents the challenges posed by the absorption of EUV light by all materials due to its high photon energy, which limits the availability of transmissive optics. To address this, ultrathin metasurfaces are introduced, consisting of millions of high-refractive-index nanopillars on flat substrates. These metasurfaces allow for the manipulation of light's spatial phase on a sub-wavelength scale, a technique that is transforming visible light handling. The lecture further explores the potential of silicon holes as guiding structures for EUV light, detailing the creation and characterization of metaoptics for 50-nm radiation. The instructor highlights the manufacturing processes and the various applications that arise from these advancements, marking a significant step towards universal transmissive optics in the EUV spectrum.