Published Online September 1 2011
< Science Express Index
Science DOI: 10.1126/science.1210713
Research Article
Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction
Nanfang Yu1,
Patrice Genevet1,2,
Mikhail A. Kats1,
Francesco Aieta1,3,
Jean-Philippe Tetienne1,4,
Federico Capasso1,
Zeno Gaburro1,5
+ Author Affiliations
1School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
2Institute for Quantum Studies and Department of Physics, Texas A&M University, College Station, TX 77843, USA.
3Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
4Laboratoire de Photonique Quantique et Moléculaire, Ecole Normale Supérieure de Cachan and CNRS, 94235 Cachan, France.
5Dipartimento di Fisica, Università degli Studi di Trento, via Sommarive 14, 38100 Trento, Italy.
Abstract
Conventional optical components rely on gradual phase shifts accumulated during light propagation to shape light beams. New degrees of freedom are attained by introducing abrupt phase changes over the scale of the wavelength. A two-dimensional array of optical resonators with spatially varying phase response and subwavelength separation can imprint such phase discontinuities on propagating light as it traverses the interface between two media. Anomalous reflection and refraction phenomena are observed in this regime in optically thin arrays of metallic antennas on silicon with a linear phase variation along the interface, in excellent agreement with generalized laws derived from Fermat's principle. Phase discontinuities provide great flexibility in the design of light beams as illustrated by the generation of optical vortices using planar designer metallic interfaces.
Received for publication 5 July 2011.
Accepted for publication 19 August 2011.