Amplification of high-harmonic radiation by x-ray amplifiers

We report the theoretical demonstration for an injection-seeded x-ray amplification, in which the output of high-harmonic generation serves as the seed amplified by the available x-ray amplifiers. We simulated the amplification process numerically in terms of the gain saturation and broadening. We found that if the seed is well matched with the amplifier temporally, spatially, and spectrally, and the intensity is up to 10(-5) of the saturation parameter, it is possible to achieve the output with highly improved spatial coherence over the full transversal dimension. The temporal coherence can be enhanced as long as the linewidth of the seed is narrower than that of the amplified spontaneous emission. The output power can be improved substantially for unsaturated amplifications. The matching between the seed and the amplifier is discussed. The scheme of chirped-pulse x-ray amplification for the production of ultrashort-pulsed high-power x-ray lasers is proposed. (C) 1996 Optical Society of America.OpticsSCI(E)1ARTICLE122852-28621