Tydex, a Russian company, is engaged in the research and development, production, and manufacturing of various THz optical lenses. It can provide off-axis parabolic mirrors, filters, polarizers, windows, lenses, prisms, waveplates, beam splitters, reflectors, and Fresnel lenses for terahertz applications. In addition, it also offers terahertz attenuators and terahertz broadband phase converters