Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction

• Published in: Science (American Association for the Advancement of Science) Vol. 334; no. 6054; pp. 333 - 337
• Main Authors: Yu, Nanfang, Genevet, Patrice, Kats, Mikhail A., Aieta, Francesco, Tetienne, Jean-Philippe, Capasso, Federico, Gaburro, Zeno
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 21.10.2011; The American Association for the Advancement of Science
• Subjects: Angle of incidence; Antenna arrays; Antennas; Arrays; Discontinuity; Edge and boundary effects; reflection and refraction; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laws; Light; Light beams; Optical reflection; Optics; Phase shift; Phase transitions; Physics; Propagation; Reflection; Refraction; Symmetry; Wave optics; Wave propagation, transmission and absorption; Wave refraction; Wavelengths; Optical beam; Electromagnetic wave refraction; Electromagnetic wave propagation; Phase shift; Optical resonators; Fermat principle; Subwavelength; Electromagnetic wave reflection; Silicon; Optical vortex
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1210713

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, which are 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 through use of planar designer metallic interfaces.