Polarisation of THz synchrotron radiation: from its measurement to control

TL;DR

This study investigates the polarization characteristics of THz synchrotron radiation, demonstrating measurement techniques, comparing with theory, and exploring 3D-printed polarizers for controlling THz beam polarization.

Contribution

It introduces the use of 3D-printed polymer polarizers and compares experimental polarization data with theoretical models for synchrotron THz radiation.

Findings

Linearly polarized component contributes up to 22%

3D-printed polarizers show spectral dichroic ratios > 1 and < 1

Metal-coated 3D-printed elements enable polarization control

Abstract

Polarisation analysis of synchrotron THz radiation was carried out with a standard stretched polyethylene polariser and revealed that the linearly polarised (horizontal) component contributes up to 22 +/- 5% to the circular polarised synchrotron emission extracted by a gold-coated mirror with a horizontal slit inserted near a bending magnet edge. Comparison with theoretical predictions shows a qualitative match with dominance of the edge radiation. Grid polarisers 3D-printed out of commercial acrilic resin were tested for the polariser function and showed spectral regions where the dichroic ratio DR > 1 and < 1 implying importance of molecular and/or stress induced anisotropy. Metal-coated 3D-printed THz optical elements can find a range of applications in intensity and polarisation control of THz beams.