Analytical theory of sub-fs pulse formation in a seeded hydrogen-like plasma-based X-ray laser dressed by an infrared field

TL;DR

This paper develops an analytical model for sub-femtosecond pulse formation in a plasma-based X-ray laser dressed by an infrared field, highlighting optimal conditions for generating high-contrast attosecond pulses.

Contribution

It presents the first analytical theory combined with numerical validation for sub-fs pulse formation in a plasma X-ray laser with infrared dressing.

Findings

Peak intensity exceeds 10^10-10^11 W/cm^2

Pulse duration ranges from 400 to 600 attoseconds

Optimal conditions minimize spontaneous emission effects

Abstract

We derive the analytical theory describing the process of sub-femtosecond pulse formation from a quasi-monochromatic seeding extreme ultraviolet (XUV) radiation, which propagates in active medium of a hydrogen-like plasma-based X-ray laser dressed by a strong infrared laser field. We discuss the ultimate capabilities and limitations of this process on the basis of the derived analytical solution and extensive numerical studies for the case of Li2+ plasma-based X-ray laser with a carrier wavelength 13.5nm. We analyze the role of plasma dispersion and find the optimal conditions for the formation of attosecond pulses with the highest contrast. Under the optimal conditions, the influence of amplified spontaneous emission from the active medium is negligible. The peak intensity of the produced XUV pulses can exceed 10^10-10^11 W/cm^2, while the duration of pulses varies in the range of 400-600 as.