"Laser like" spatial coherence of a high-flux, ultrashort-pulse, EUV source

Summary form only given. High-harmonic generation is a convenient method for generating coherent light in the extreme-ultraviolet (EUV) region of the spectrum, using a small-scale ultrafast laser-based apparatus. Recent advances in using hollow waveguides for HHG have demonstrated conversion efficiency of >10/sup -5/ into a well-collimated EUV beam. In this work, we demonstrate that this beam exhibits full spatial coherence to the limits of our measurement capability, making this source the most coherent light source ever in this region of the spectrum. This contrasts with previous measurements of the coherence of HHG radiation generated in a gas-jet geometry, which measured substantially-degraded spatial coherence. We also demonstrate a new and simple technique for measuring the spectrum of this EUV emission by deconvolution of a double-slit interference pattern for the first time.