Subwavelength silicon terahertz optics for generation of coherent beams with pre-given polarization state

Coherent terahertz beams with radial polarization of 1,2 and 3 orders have been generated by the use of silicon subwavelength diffractive optical elements (DOEs). The beam of terahertz Novosibirsk Free Electron Laser was used as the illuminating beam. Experimental results are in good agreement with the results of computer simulation.