title: Aspheric lenses for terahertz imaging.
abstract: We present novel designs for aspheric lenses used in terahertz (THz) imaging. As different surfaces result in different beam shaping properties and in different losses from reflection and absorption, the resultant imaging resolution (i.e. the focal spot size) depends critically on the design approach. We evaluate the different lens designs using Kirchhoff's scalar diffraction theory, and test the predictions experimentally. We also show that our lenses can achieve sub-wavelength resolution. While our lens designs are tested with THz radiation, the design considerations are applicable also to other regions of the electro-magnetic spectrum.
authors.affiliation: Physics Department, University of Auckland, Private Bag 92019, Auckland, New Zealand. ylo010@aucklanduni.ac.nz
authors.forename: Yat Hei
authors.initials: YH
authors.lastname: Lo
authors.forename: Rainer
authors.initials: R
authors.lastname: Leonhardt
mesh_terms: D000042:Absorption; D003198:Computer Simulation; D004867:Equipment Design; D007909:Lenses; D007910:Lenses, Intraocular; D015233:Models, Statistical; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000295:instrumentation*; D011095:Polyethylenes / Q000737:chemistry; D012029:Refraction, Ocular
chemical_list: D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene