Soft X-ray Vortex Beam detected by In-line Holography

TL;DR

This paper demonstrates the use of in-line holography to detect and analyze soft x-ray vortex beams with orbital angular momentum, enabling detailed characterization of their phase structure.

Contribution

It introduces a novel in-line holography method for soft x-ray vortex beams, allowing direct visualization and analysis of their spiral phase distribution.

Findings

Fork-shaped interference fringes confirm vortex beam formation

Successful extraction of spiral phase distribution

Potential application in topological magnet characterization

Abstract

We demonstrate the in-line holography for soft x-ray vortex beam having an orbital angular momentum. A hologram is recorded as an interference between a Bragg diffraction wave from a fork grating and a divergence wave generated by a Fresnel zone plate. The obtained images exhibit fork-shaped interference fringes, which confirms the formation of the vortex beam. By analyzing the interference image, we successfully obtained the spiral phase distribution. The results demonstrate that the in-line holography technique is promising for the characterization of topological magnets, such as magnetic skyrmions.