Report

Ultraviolet surprise: Efficient soft x-ray high-harmonic generation in multiply ionized plasmas

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Science  04 Dec 2015:
Vol. 350, Issue 6265, pp. 1225-1231
DOI: 10.1126/science.aac9755

Short wavelengths birth shorter ones

The shortest laser pulses—with durations measured in attoseconds—arise from a process termed high-harmonic generation (HHG). Essentially, a longer, “driving” pulse draws electrons out of gaseous atoms like a slingshot, and, when they ricochet back, light emerges at shorter wavelengths. Most HHG has been carried out using light near the visible/infrared boundary for the driving pulse. Popmintchev et al. used an ultraviolet driving pulse instead, which yielded an unexpectedly efficient outcome. These results could presage a more generally efficient means of creating x-ray pulses for fundamental dynamics studies as well as technological applications.

Science, this issue p. 1225