Generation of high-power attosecond x-ray FEL pulses carrying orbital angular momentum

TL;DR

This paper proposes a method to generate high-power, attosecond x-ray pulses with orbital angular momentum using a self-seeded FEL scheme, enabling advanced probing of matter with high intensity and short duration.

Contribution

The paper introduces a novel approach combining SSOAM with attosecond pulse generation to produce intense x-ray vortices with high power and ultrashort duration.

Findings

Achieved peak powers over 100 GW for x-ray OAM pulses

Produced pulses with durations around hundreds of attoseconds

Demonstrated the feasibility through numerical simulations

Abstract

X-ray beams carrying orbital angular momentum (OAM), are emerging as a powerful tool to probe matter. Recently, a method called self-seeded FEL with OAM (SSOAM) has been proposed to generate high-power x-ray OAM pulses, which places the traditional optical elements in the linear regime of the FEL amplification process before saturation to reduce the thermal load of the optical element. In this work, we propose to utilize the SSOAM scheme to produce attosecond x-ray vortices with high intensity. Numerical simulations demonstrate the x-ray OAM pulses with peak powers of more than one hundred gigawatts and a pulse duration of the order of hundred attoseconds can be achieved using the proposed method.