title: Aberration-free laser beam in the soft x-ray range.
abstract: By seeding an optical-field-ionized population-inverted plasma amplifier with the 25th harmonic of an IR laser, we have achieved what we believe to be the first aberration-free laser beam in the soft x-ray spectral range. This laser emits within a cone of 1.34 mrad(1/e(2)) at a repetition rate of 10 Hz at a central wavelength of 32.8 nm. The beam exhibits a circular profile and wavefront distortions as low as lambda/17. A theoretical analysis of these results shows that this high beam quality is due to spatial filtering of the seed beam by the plasma amplifier aperture.
authors.affiliation: Laboratoire d'Optique Appliquée (LOA), ENSTA-Ecole Polytechnique, Chemin de la Hunière,91761 Palaiseau, France. jean-philippe.goddet@ensta.fr
authors.forename: J Ph
authors.initials: JP
authors.lastname: Goddet
authors.forename: S
authors.initials: S
authors.lastname: Sebban
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authors.initials: J
authors.lastname: Gautier
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authors.lastname: Zeitoun
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authors.lastname: Valentin
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authors.lastname: Tissandier
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authors.lastname: Marchenko
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authors.lastname: Lambert
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authors.lastname: Ribières
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authors.lastname: Douillet
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authors.lastname: Lefrou
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authors.lastname: Iaquaniello
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authors.lastname: Burgy
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authors.lastname: Maynard
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authors.lastname: Cros
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authors.lastname: Robillard
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authors.lastname: Mocek
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authors.lastname: Nejdl
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authors.lastname: Kozlova
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authors.lastname: Jakubczak