Electromagnetic interactions between a fast electron beam and metamaterial cloaks

Relativistic energy loss and photon emission in the interaction of ideal and nonideal metamaterial cloaks with an external electron beam are studied based on the classical electrodynamics. The effects of various imperfect parameters on the efficiency of the cloak are emphasized. The energy-loss spectra and the photon emission for such structures with the different combinations of electron velocity and impact parameter are calculated. It is shown that the efficiency of nonideal electromagnetic cloaks and the effect of various nonideal parameters on the cloak invisibility can be exhibited in the electron energy loss spectroscopy. This means that the properties of cloak can be explored by scanning transmission electron microscopy.