Influence of Detuning of the Seeding VUV Radiation
from the Resonance on Formation of Subfemtosecond Pulses
in the Active Medium of the Plasma-Based X-Ray Laser Dressed
by an Intense IR Field
I. R. Khairulina, b, *, V. A. Antonova, c, M. Yu. Ryabikina, b, c, and O. A. Kocharovskayad
a Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, 603950 Russia
b Nizhny Novgorod State University, Nizhny Novgorod, 603950 Russia
c Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991 Russia
d Department of Physics and Astronomy, Texas A&M Universityn, College Station, TX 77843-4242 USA
Correspondence to: *e-mail: khairulinir@ipfran.ru
Received 15 November, 2020
Abstract—We have studied the influence of detuning of quasimonochromatic seeding vacuum ultraviolet (VUV)/X-ray radiation from the frequency of the inverted transition of the hydrogen-like active medium of the plasma-based X-ray laser dressed by an intense infrared (IR) laser field on the formation of a subfemtosecond pulse train. For the active medium (plasma) of Li2+ ions with the inverted transition wavelength of 13.5 nm, it is demonstrated that the use of the seeding radiation detuned from the resonance by double the frequency of the modulating field allows a fourfold increase in the peak intensity of the formed pulses relative to the case of the exact resonance, while the maximum contrast is preserved.
Keywords: subfemtosecond pulses, VUV radiation, plasma-based X-ray laser, strong optical field, Stark effect, generation of combination frequencies
DOI: 10.3103/S1541308X21030079