Experimental investigation of polarization and spatial properties of coherent Cherenkov diffraction radiation in super-radiant regime

In this paper, we present the experimental studies of fundamental properties of super-radiant coherent Cherenkov diffraction radiation in the millimeter-wavelength range. Experimental work was performed at the MT-25 microtron in Dubna. We have illustrated and discussed the spatial distribution of the radiation in both the pre-wave zone and the far-field zone, and present an investigation into the polarization characteristics of super-radiant spectral lines at various frequencies. The experimental results have been compared with the theoretical model based on polarization current approach. • The first application of a super-radiant regime for measuring spatial polarization properties of Cherenkov Diffraction Radiation (ChDR). • Investigation of the ChDR angular distribution in the pre-wave zone and a detailed comparison with analytical theory. • The first observation of polarization properties of ChDR demonstrating the dominance of linear polarization.