Abstract
Electron and ion density gratings induced by two intersecting ultrashort laser pulses at intensities of 1016 W/cm2 or lower are investigated. The ponderomotive force generated by the inhomogeneous intensity distribution in the intersecting region of the interfering pulses produces deep electron and ion density modulations at a wavelength less than a laser wave-length in vacuum. Dependence of the density modulation on the plasma densities, temperatures, and the ion mass, as well as the laser pulse parameters are studied analytically and by particle-in-cell simulations. It is found that the density peaks of such gratings can be a few times that of the initial plasma density and last as long as a few picoseconds. It is also demonstrated that the scattering of signal pulses by such a bulk density grating results in high-harmonic generation. The density gratings may be incorporated into ion-ripple lasers [K.R. Chen and J.M. Dawson, Phys. Rev. Lett. 68, 29 (1992)] to generate ultrashort X-ray pulses of a few angstroms by using electron beams at only a few tens of MeV only.
Original language | English (US) |
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Pages (from-to) | 673-680 |
Number of pages | 8 |
Journal | Applied Physics B: Lasers and Optics |
Volume | 77 |
Issue number | 6-7 |
DOIs | |
State | Published - Nov 2003 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- General Physics and Astronomy