Temporal coherence of ultrashort high-order harmonic pulses
Abstract
The measurements of the temporal coherence of high-order harmonics produced by focusing 100 fs pulses of a titanium-sapphire laser into an argon gas jet are presented. The experiment consists of measuring the visibility of the interference fringes, produced when two spatially separated harmonic sources interfere in the far field, as a function of the time delay between the two sources. From the measurements, long coherence times are found, comparable to the expected pulse durations of the harmonics, showing that almost transform-limited pulses are produced in the extreme ultraviolet and that the process of harmonic generation does not introduce significant phase distortions in the generated short-wavelength pulses.
This paper has been withdrawn.