Efficient XUV out-coupling mechanisms for intra-oscillator HHG J. Drs, J. Fischer, M. Müller, N. Modsching, V. J. Wittwer and T. Südmeyer EPJ Web Conf., 267 (2022) 01021 Published online: 18 October 2022 DOI: 10.1051/epjconf/202226701021