# Attosecond Pulse Amplification in a Plasma-Based X-Ray Laser Dressed by an Infrared Laser Field

## TL;DR

This paper proposes a plasma-based X-ray laser technique that amplifies attosecond pulse trains generated by high-harmonic generation, using IR field modulation to achieve significant amplification and pulse isolation.

## Contribution

It introduces a novel method to amplify attosecond pulses in a plasma medium by IR-induced frequency modulation, enabling substantial amplification and pulse isolation.

## Key findings

- Amplification of attosecond pulse trains by two orders of magnitude.
- Pulse durations can be as short as 100 attoseconds.
- Single pulse isolation is feasible during amplification.

## Abstract

We suggest a technique to amplify a train of attosecond pulses, produced by high-harmonic generation (HHG) of an infrared (IR) laser field, in an active medium of a plasma-based X-ray laser. This technique is based on modulation of transition frequency of the X-ray laser by the same IR field, as used to generate the harmonics, via linear Stark effect, which results in redistribution of the resonant gain and simultaneous amplification of a wide set of harmonics in the incident field. We propose an experimental implementation of the suggested technique in active medium of C5+ ions at wavelength 3.4 nm in the "water window" range and show the possibility to amplify by two orders of magnitude a train of attosecond pulses with pulse duration down to 100 as. We show also a possibility to isolate a single attosecond pulse from the incident attosecond pulse train during its amplification in optically deep modulated medium.

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Source: https://tomesphere.com/paper/1904.07034