A waveguide metasurface based quasi-far-field transverse-electric superlens  

作　　者：Yechuan Zhu Xiaolin Chen Weizheng Yuan Zhiqin Chu Kwok-yin Wong Dangyuan Lei Yiting Yu 

机构地区：[1]Shaanxi Province Key Laboratory of Micro and Nano Electro-Mechanical Systems,Northwestern Polytechnical University,Xi’an 710072,China [2]Key Laboratory of Micro/Nano Systems for Aerospace(Ministry of Education),Northwestern Polytechnical University,Xi’an 710072,China [3]Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test,Xi’an Technological University,Xi’an 710021,China [4]Department of Optical Engineering,School of Electronic Science&Applied Physics,Hefei University of Technology,Hefei 230601,China [5]Department of Applied Biology and Chemical Technology,The Hong Kong Polytechnic University,Hung Hom,Hong Kong 999077,China [6]Department of Electrical and Electronic Engineering,Joint Appointment with School of Biomedical Sciences,The University of Hong Kong,Hong Kong 999077,China [7]Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong 999077,China

出　　处：《Opto-Electronic Advances》2021年第10期24-29,共6页光电进展（英文）

基　　金：support by the National Natural Science Foundation of China(52075410,51975483,51622509);the Fundamental Research Funds for the Central Universities(31020190504001);the 111 Project(B13044),the Dean Fund(2019GDYJY05);the Collaborative Innov-ation Center Project of Shaanxi Provincial Department of Education(20JY031);the Natural Science Basic Research Plan in Shaanxi Province of China(2018JQ6012);the Hong Kong Polytechnic University through the“Life Science Research”project(1-ZVH9),and the City University of Hong Kong(9610456).

摘　　要：The imaging capability of conventional lenses is mainly limited by the diffraction of light,and the so-called superlens has been developed allowing the recovery of evanescent waves in the focal plane.However,the remarkable focusing behavi-or of the superlens is greatly confined in the near-field regime due to the exponential decay of evanescent waves.To tackle this issue,we design a waveguide metasurface-based superlens with an extraordinary quasi-far-field focusing capability beyond the diffraction limit in the present work.Specifically,we analyze the underlying physical mechanism and provide experimental verification of the proposed superlens.The metasurface superlens is formed by an array of gradient nanoslits perforated in a gold slab,and supports transverse-electric(TE)waveguide modes under linearly polar-ized illumination along the long axis of the slits.Numerical results illustrate that exciting such TE waveguide modes can modulate not only optical phase but also evanescent waves.Consequently,some high-spatial-frequency waves can con-tribute to the focusing of the superlens,leading to the quasi-far-field super-resolution focusing of light.Under 405 nm illu-mination and oil immersion,the fabricated superlens shows a focus spot of 98 nm(i.e.λ/4.13)at a focal distance of 1.49μm(i.e.3.68λ)using an oil immersion objective,breaking the diffraction limit ofλ/2.38 in the quasi-far field regime.The developed metasurface optical superlens with such extraordinary capabilities promises exciting avenues to nanolitho-graphy and ultra-small optoelectronic devices.

关 键 词：SUPERLENS metasurface WAVEGUIDE quasi-far-field super-resolution focusing breaking the diffraction limit 

分 类 号：TH74[机械工程—光学工程]