Ultrafast lensless imaging with plasmonic enhanced XUV generation

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The IPEX project proposes to study the extreme ultraviolet (XUV) coherent light generation from MHz repetition-rate lasers assisted by plasmonic resonances to achieve local enhancements of electric fields. In 2008, Kim et al. used bowtie nano-antennae to produce high-harmonic (HH) radiation at a repetition rate of 75 MHz [Kim et al. Nature 2008]. Recently, the group of Ropers (Sivis et al., Nature 2012), using nearly identical conditions as Kim et al., observed XUV emission from the gas-exposed nanostructures, but came to a different conclusion. They attributed the XUV radiation to incoherent emission lines of neutral and ionized atoms.The IPEX project will contribute to resolve this controversy by examining the coherence properties of such a nanostructure-based XUV source. We will use the source to perform first experiments involving ultrafast coherent diffractive imaging. We will start with 2D and continue with 3D static test objects to study ultrafast nanoscale motions in materials. Furthermore, we will characterize the ultrashort time structure of the harmonic emission and exploit it as a probe for attosecond plasmonic dynamics utilizing a self-probing atomic clock technique. The methodology will rely on novel nano-structures, strong field physics, and state-of the art ultrafast laser oscillators.Note that this project is only possible by combining the complementary expertise of the two partners CEA (France) and IO Hannover (Germany). On one hand, IO Hannover has a new lab facility to investigate HH generation (HHG) through nanoplasmonic field enhancement with peer-reviewed promising results. On the other hand, CEA has demonstrated coherent diffractive imaging and magnetic scattering technique in single shot and with sub-100 nm spatial resolution using an intense HHG source. With a repetition rate in the Mhz range, a potentially high brilliance in the XUV regime, and ultrashort pulse duration, plasmonic HH sources present a unique and inexpensive alternative to large-scale facilities such as synchrotrons, FELs, or terawatt laser-driven XUV sources.