Abstract: 
According to the particle conception, visible light consists of photons with spin h/2π. In fact, the spin of visible light can not only be verified by spectroscopic means but also directly by macroscopic measurement of angular momentum. However, an experimental verification of the photon spin of electromagnetic radiation of very large wave lengths has not yet been accomplished. Nevertheless, today the quantity of the photon spin is considered constant throughout all wave lengths. The question is if the photon spin with growing wave lengths and with a photon mass approaching zero can retain the constant value h/2π. For this reason, we set ourselves the goal to measure the spin of radio wave photons. Therefore, we also had to use a macroscopic measurement method of the angular momentum (scattering of circular polarized radio waves by a thin aluminum disc), since methods of measurement using atomic physics are not possible at very large wave lengths. Finally, we further refer to the experiments of the past decades with satellites: Presupposed a frequency-independent photon spin there should be observable corresponding angular momentum effects on circular polarized transmitting satellites. 

Cite this article

Krebs A., Krebs C. The photon spin - a natural constant? Science Advance (2023). https://doi.org/10.59208/sa-2023-03-14-2