Generation of extreme ultraviolet continuum radiation driven by a sub-10-fs two-color field.

Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-0061, Japan.
Optics Express (Impact Factor: 3.53). 09/2006; 14(16):7230-7. DOI: 10.1364/OE.14.007230
Source: PubMed

ABSTRACT We have proposed and demonstrated a novel approach for generating high-energy extreme-ultraviolet (XUV) continuum radiation. When a two-color laser field consisting of a sub-10-fs fundamental and its parallel-polarized second harmonic was applied to high-order harmonic generation in argon, a continuum spectrum centered at 30 nm was successfully obtained with an energy as high as 10 nJ. This broadband emission indicates the possibility of generating intense single attosecond pulses in the XUV region.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: By numerically solving the time-dependent Schrödinger equation for helium gas in a special two-color laser field, which is synthesized by a long (9 fs) driving pulse and a short (6 fs) controlling pulse, we discuss the influence of the carrier-envelope phase, frequency, and the intensity of the controlling pulse on the generation of harmonic spectra and isolated attosecond pluses. In the cutoff region, two or three plateaus can be controlled by optimizing these laser parameters, and an ultrabroad supercontinuum harmonic spectrum with a bandwidth of 800 eV can be produced, which can support an ultrashort isolated 4.5 as pulse generation by Fourier transformation. Furthermore, using classical ionizing and returning energy maps, time–frequency analyses are presented to explain the underlying physical mechanisms.
    Journal of Modern Optics 11/2012; 59(19):1640-1649. · 1.17 Impact Factor
  • Source
    G Lambert, A Andreev, J Gautier, L Giannessi, V Malka, A Petralia, S Sebban, S Stremoukhov, F Tissandier, B Vodungbo, Ph Zeitoun
    [Show abstract] [Hide abstract]
    ABSTRACT: High harmonic generation in gases is developing rapidly as a soft X-ray femtosecond light-source for applications. This requires control over all the harmonics characteristics and in particular, spatial properties have to be kept very good. In previous literature, measurements have always included several harmonics contrary to applications, especially spectroscopic applications, which usually require a single harmonic. To fill this gap, we present here for the first time a detailed study of completely isolated harmonics. The contribution of the surrounding harmonics has been totally suppressed using interferential filtering which is available for low harmonic orders. In addition, this allows to clearly identify behaviors of standard odd orders from even orders obtained by frequency-mixing of a fundamental laser and of its second harmonic. Comparisons of the spatial intensity profiles, of the spatial coherence and of the wavefront aberration level of 5ω at 160 nm and 6ω at 135 nm have then been performed. We have established that the fundamental laser beam aberrations can cause the appearance of a non-homogenous donut-shape in the 6ω spatial intensity distribution. This undesirable effect can be easily controlled. We finally conclude that the spatial quality of an even harmonic can be as excellent as in standard generation.
    Scientific Reports 01/2015; 5:7786. · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: With a theoretical model including both the single-atom and collective responses to the two-color laser field, we investigate the influence of macroscopic effects on the generation of isolated attosecond pulse. It is shown that broadband supercontinuous high harmonics can be produced by controlling the ionization or acceleration step of high-order harmonic generation (HHG). Utilizing the broadband supercontinuum, isolated sub-100 attosecond pulse can be generated. We also investigate the influence of atomic density on the enhancement of HHG. Moreover, the distortion and dephasing of two-color field in the propagation of ionized gas medium are also discussed.
    Physical Review A 04/2009; · 2.99 Impact Factor

Full-text (2 Sources)

Available from
Sep 26, 2014