Subpicosecond and Sub-Angstrom Time and Space Studies by Means of Light, X-ray, and Electron Interaction with Matter

This Perspective article considers an experimental system that consists of ultrafast optical, electron, and X-ray time-resolved components. These techniques are used simultaneously on the same sample to study, in real time, the events that occur immediately upon disturbance with an ultrafast optical pulse. Excited states and metastable species are generated on the surface, and the electrical and mechanical waves propagating through the sample are recorded with subpicosecond and sub-Angstrom resolution. The characteristic of each technique is briefly described as a means of introducing the experimental system that intergrates these techniques. The processes evolved after femtosecond excitation of a Au single crystal have been monitored by these techniques. The data presented show changes with a resolution of 0.3 +/- 0.1 ps in optical thermoreflectance, 1.0 +/- 0.2 ps in electron Bragg diffraction, and 0.6 +/- 0.1 ps in X-ray diffraction intensity accompanying shift and broadening.