Note: Soft X-ray transmission polarizer based on ferromagnetic thin films

Area of Science:

• Physics
• Materials Science
• Optics

Background:

• Synchrotron and free-electron laser beamlines often lack direct circularly polarized light sources.
• Circularly polarized X-rays are crucial for techniques like X-ray magnetic circular dichroism (XMCD) and holographic imaging.
• Developing efficient methods to generate elliptically polarized soft X-rays is essential for advanced research.

Purpose of the Study:

• To present a novel transmission polarizer for generating elliptically polarized soft X-ray radiation from linearly polarized light.
• To investigate the degree of ellipticity achieved when linearly polarized radiation passes through a cobalt thin film.
• To demonstrate a versatile method applicable to various absorption edges exhibiting the XMCD effect.

Main Methods:

• Utilizing a cobalt thin film as a transmission polarizer for soft X-ray radiation.
• Performing experiments at the Co L3-edge (778 eV) resonant photon energy.
• Employing a polarization analyzer based on the directional dependence of photoelectrons emitted from a gas target to determine transmitted polarization.

Main Results:

• Successfully produced elliptically polarized soft X-ray radiation from linearly polarized incident light.
• Quantified the degree of ellipticity generated by the cobalt thin film.
• Confirmed the feasibility of creating elliptically polarized radiation using magnetic elements at specific absorption edges.

Conclusions:

• The developed transmission polarizer effectively generates elliptically polarized soft X-rays.
• This technique provides a valuable alternative for beamlines not offering direct circularly polarized light.
• The method is broadly applicable for XMCD measurements and other polarization-sensitive X-ray techniques.