Chinese physicists achieve first 2D mapping of gamma ray polarization in relativistic slant collisions

Physicists at the Shanghai Synchrotron Facility use 45-degree slant collisions to decode polarization transfer in high-energy gamma rays.

By: AXL Media

Published: Apr 28, 2026, 9:37 AM EDT

Source: Information for this report was sourced from EurekAlert!

Decoding the Fundamental Transfer of Light Polarization in Atomic Matter

A research team in China has achieved a milestone in fundamental light matter interaction by visualizing the complex transfer of polarization during particle collisions. While polarization is a familiar concept in daily optics, such as 3D cinema and satellite communications, its behavior during intense interactions with high speed electrons has remained difficult to map precisely. By studying how low energy photons interact with relativistic electrons, the team has successfully demonstrated how the "orderly wave" of light can be manipulated and transferred to create high energy radiation.

Innovating with Oblique Scattering at the Shanghai Synchrotron Facility

The experiment utilized a high quality 3.5 GeV electron beam from the Shanghai Synchrotron Radiation Facility to perform inverse Compton scattering. Departing from traditional head on collision models, the scientists innovatively adopted a 45-degree slant collision geometry. This oblique approach allowed the researchers to observe how photons "bounce off" electrons at an angle, transforming into high energy gamma rays. This setup provided a unique perspective on the spatial distribution of light properties that head on collisions typically obscure.

Visualizing the Two Dimensional Signature of Gamma Ray Intensity

For the first time, the team achieved a detailed full two dimensional measurement of the resulting gamma rays, focusing on their intensity, degree of polarization, and polarization angle. The resulting "polarization signature" revealed a highly organized physical structure. According to the study, the center of the beam reached near perfect 100% polarization with a locked direction, while the peripheral regions displayed a more complex and asymmetric pattern. This detailed mapping offers a visual confirmation of quantum electrodynamics (QED) predictions for non head on particle collisions.