Torres Landívar, VíctorPacheco-Peña, VíctorRodríguez Ulibarri, PabloNavarro Cía, MiguelBeruete Díaz, MiguelSorolla Ayza, MarioEngheta, Nader2018-10-232018-10-2320131094-4087 (Electronic)10.1364/OE.21.009156https://academica-e.unavarra.es/handle/2454/31109An epsilon-near-zero graded-index converging lens with planar faces is proposed and analyzed. Each perfectly-electric conducting (PEC) waveguide comprising the lens operates slightly above its cut-off frequency and has the same length but different cross-sectional dimensions. This allows controlling individually the propagation constant and the normalized characteristic impedance of each waveguide for the desired phase front at the lens output while Fresnel reflection losses are minimized. A complete theoretical analysis based on the waveguide theory and Fermat’s principle is provided. This is complemented with numerical simulation results of two-dimensional and three-dimensional lenses, made of PEC and aluminum, respectively, and working in the terahertz regime, which show good agreement with the analytical work.11 p.application/pdfeng© 2013 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.Epsilon-near-zero graded-index converging lensesinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess