Ultrafast Extreme Ultraviolet (EUV) radiation is used to probe transient surface phenomenon in three experimental geometries. Optical irradiation of the sample surface generates thermal and acoustic transients that are subsequently probed with a time-delayed EUV pulse. In all experimental geometries we show excellent signal-to-noise ratios (>10:1) and increased sensitivity to surface deformations (<.02nm) directly attributable to the reduced wavelength of the probing light.
High harmonic generation (HHG) is a useful source of coherent light in the extreme ultraviolet (EUV) region of the spectrum. However, both the conversion efficiency and the highest achievable photon energy have in the past been limited in the past by the inability to phase-match the frequency conversion process. In this paper, we summarize recent results on the development of new techniques for phase-matching the high-harmonic conversion process. We also summarize finding from three series of experiments that make use of the coherent EUV light generated using HHG: 1) probing of acoustic dynamics in materials; 2) monitoring of chemical dynamics at surfaces using photoelectron spectroscopy; and 3) time-resolved plasma imaging.