Related Experiment Video
Updated: Apr 26, 2026

Demonstration of Equal-Intensity Beam Generation by Dielectric Metasurfaces
Published on: June 7, 2019
Negative refraction and planar focusing based on parity-time symmetric metasurfaces
Romain Fleury1, Dimitrios L Sounas1, Andrea Alù1
1Department of Electrical & Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
Abstract:
We introduce a new mechanism to realize negative refraction and planar focusing using a pair of parity-time symmetric metasurfaces. In contrast to existing solutions that achieve these effects with negative-index metamaterials or phase conjugating surfaces, the proposed parity-time symmetric lens enables loss-free, all-angle negative refraction and planar focusing in free space, without relying on bulk metamaterials or nonlinear effects. This concept may represent a pivotal step towards loss-free negative refraction and highly efficient planar focusing by exploiting the largely uncharted scattering properties of parity-time symmetric systems.
Related Concept Videos
Reflective Property of Parabolas
Focusing of Light in the Eye
Centroid for the Paraboloid of Revolution
The centroid for the paraboloid of revolution is the point where all the mass of the paraboloid is concentrated. This centroid is important for engineering applications, as it determines how forces are...

