TERAHERTZ-WAVE OPTICAL ELEMENT

摘要

Provided is an optical element for terahertz waves that compresses a terahertz-wave incident beam to a wavelength equal to or less than half the wavelength thereof and allows the passage thereof. The optical element is characterized in that: the optical element is equipped with a substrate that terahertz waves can penetrate, and a conductive film that covers a surface on one side of the substrate and is capable of blocking terahertz waves; the film has an aperture provided to a circular area, and a plurality of ring-shaped grooves provided to the film surface and concentric with the circular area, with the radii thereof increasing by a fixed increment; and four or more fan-shaped protruding parts having arcs of which the radius of curvature is equal to the radius of the circular area are arranged in the circular area at regular intervals, and oriented toward the centre of the circle without touching each other, with the arcs in contact with the outer circumference of the circular area.