Coherent 0.5-keV x-ray emission from helium driven by a sub-10-fs laser

M. Schnürer, Ch Spielmann, P. Wobrauschek, C. Streli, N. H. Burnett, C. Kan, K. Ferencz, R. Koppitsch, Z. Cheng, T. Brabec, F. Krausz

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Helium atoms ionized by intense few-cycle light pulses in the barrier suppression regime emit spatially coherent extreme ultraviolet continuum extending to photon energies greater than Eph = 0.5 keV (λ<2.5 nm). The high-energy end of the continuum in the range of Eph>=0.2 keV (λ<=6 nm) was characterized spectrally over a considerable dynamic range using energy-dispersive detection. The sub-10-fs laser pulse duration was found to be crucial for generating radiation with the highest photon energies at the low (<0.5 mJ) pump energy levels used in the experiments. The single-atom quantum theory of high-order harmonic generation combined with Maxwell's wave equation provides a satisfactory account for the experimental observations.

Original languageEnglish
Pages (from-to)3236-3239
Number of pages4
JournalPhysical review letters
Issue number15
Publication statusPublished - Jan 1 1998


ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Schnürer, M., Spielmann, C., Wobrauschek, P., Streli, C., Burnett, N. H., Kan, C., Ferencz, K., Koppitsch, R., Cheng, Z., Brabec, T., & Krausz, F. (1998). Coherent 0.5-keV x-ray emission from helium driven by a sub-10-fs laser. Physical review letters, 80(15), 3236-3239.