Terahertz epsilon-near-zero graded-index lens

Research output: Contribution to journalArticlepeer-review


  • Víctor Torres
  • Víctor Pacheco-Peña
  • Pablo Rodríguez-Ulibarri
  • Miguel Beruete
  • Mario Sorolla
  • Nader Engheta

Colleges, School and Institutes

External organisations

  • Universidad Pública de Navarra
  • University of Pennsylvania
  • Pennsylvania State University


An 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.


Original languageEnglish
Pages (from-to)9156-9166
Number of pages11
JournalOptics Express
Issue number7
Publication statusPublished - 8 Apr 2013