Lens Design with Silicon Wafer for Terahertz Wave Transmission

Abstract

Terahertz waves can pass through silicon wafer with less loss than traditional lenses. By selecting square, circular and sectors as building blocks, a serial of equivalent lenses for terahertz wave transmission were designed in the vertical plane of the silicon wafer, including hemispherical convex, concave mirror, triangular prism and spherocylinder lenses. The lens’ 2-D design in this work is much simpler than its actual 3-D shape. Besides high transmit ability, silicon wafer also has high refractive index. When a lens is oriented horizontally, it can act as a graded-index photonic crystal waveguide, due to the existence of a band gap, especially for cylinder and prism lens.