Compact diffractive optical components for terahertz beam manipulation

Zone plates of the conventional design and the complex with integrated band-pass filter apertures were fabricated on the metal film and highly resistive silicon substrate using the direct laser writing. The focusing performance of the diffractive components was studied measuring the 0.6 THz frequency beam profiles along the optical axis. The compact lenses with the focal length of 5 and 10 mm and the numerical aperture up to 0.5 was experimentally demonstrated with the preference for the silicon components due to less pronounced standing waves effect between the detector and the zone plate.