Ultra-thin, planar, Babinet-inverted plasmonic metalenses  

作　　者：Xingjie Ni Satoshi Ishii Alexander V Kildishev Vladimir M Shalaev 

机构地区：[1]School of Electrical and Computer Engineering and Birck Nanotechnology Center,Purdue University,West Lafayette,IN 47907,USA

出　　处：《Light(Science & Applications)》2013年第1期170-175,共6页光（科学与应用)（英文版）

基　　金：This work is partially supported by Air Force Office of Scientific Research grant FA9550-12-1-0024,U.S.Army Research Office grant 57981-PH(W911NF-11-1-0359 and grant“Flat photonics with metasurfaces”);NSF grant DMR-1120923;A V Kildishev is supported by the AFRL Materials and Manufacturing Directorate Applied Metamaterials Program with UES,Inc.

摘　　要：We experimentally demonstrate the focusing of visible light with ultra-thin,planar metasurfaces made of concentrically perforated,30-nm-thick gold films.The perforated nano-voids—Babinet-inverted(complementary)nano-antennas—create discrete phase shifts and form a desired wavefront of cross-polarized,scattered light.The signal-to-noise ratio in our complementary nano-antenna design is at least one order of magnitude higher than in previous metallic nano-antenna designs.We first study our proof-of-concept‘metalens’with extremely strong focusing ability:focusing at a distance of only 2.5 mm is achieved experimentally with a 4-mm-diameter lens for light at a wavelength of 676 nm.We then extend our work with one of these‘metalenses’and achieve a wavelength-controllable focal length.Optical characterization of the lens confirms that switching the incident wavelength from 676 to 476 nm changes the focal length from 7 to 10 mm,which opens up new opportunities for tuning and spatially separating light at different wavelengths within small,micrometer-scale areas.All the proposed designs can be embedded on-chip or at the end of an optical fiber.The designs also all work for two orthogonal,linear polarizations of incident light.

关 键 词：metalens nano-antennas PLASMONICS wavefront shaping 

分 类 号：TN2[电子电信—物理电子学]