Metal-grating phase plates for submillimeter radiation

A method for circularly polarizing submillimeter waves using metal gratings is proposed. Experimental results on the amplitude and phase properties of gratings are reported and their uses for converting linearly polarized submillimeter waves into circularly polarized radiation are discussed. The method has the following advantages: the gratings are easy to fabricate and to use in quasi-optical channels; their electrodynamic properties do not change with temperature; they are transparent to gases, liquids, and particle beams. Circularly polarized electromagnetic radiation is widely used in experimental physics to study gyrotropic and anisotropic media, and in radio engineering.