 This study investigates the possibility of generating atosecond pulses using plasmonic field enhancement in a nanostructured metallic funnel waveguide, with emphasis on generating isolated atosecond pulses. The finite domain time difference method was used to analyze the funnel waveguide's geometry-dependent plasmonic features, and an extended semi-classical model of high-order harmonic generation was adopted to predict the EUV spectra generated from the funnel waveguide. Simulation results showed that isolated atosecond pulses can be produced at fast repetition rates directly from a few-cycle femtosecond laser or by synthesizing a two-color laser consisting of two multi-cycle pulses of cross-polarized configuration. This article was authored by Jun Hee Choi, Sun Chul Kim in Yong Park, and others.