Supercritical metalens at h-line for high-resolution direct laser writing  

作　　者：Jichao Fu Mengting Jiang Zeng Wang Yi Fan Chen Yuanda Liu Qing Yang Steve Wu Ai Jia Sim Jiang Wang Mingxi Chen Ziyu Wang Jie Deng Xiao Song Eric Tang Kun Huang Hong Liu Jinghua Teng 

机构地区：[1]Institute of Materials Research and Engineering(IMRE),Agency for Science,Technology and Research(A*STAR),2 Fusionopolis Way,Innovis#08-03,Singapore 138634,Singapore [2]School of Microelectronics,Hefei University of Technology,Hefei 230009,China [3]Department of Optics and Optical Engineering,University of Science and Technology of China,Hefei 230026,China.

出　　处：《Opto-Electronic Science》2024年第10期14-22,共9页光电科学（英文）

基　　金：financially supported by A*STAR under IRG program(Grant No.A2083c0058)and the MTC Programmatic(Grant No.M22L1b0110);Z Wang thanks the GAP Funding(I21D1AG010);the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-049);the National Natural Science Foundation of China(Grant Nos.12134013 and 62322512);the National Key Research and Development Program of China(Grant No.2022YFB3607300);the CAS Pioneer Hundred Talents Program,and support from the University of Science and Technology of China’s Centre for Micro;Nanoscale Research and Fabrication.

摘　　要：Supercritical lens(SCL)can break the diffraction limit in the far field and has been demonstrated for high-resolution scanning confocal imaging.Its capability in sharper focusing and needle-like long focal depth should allow high-resolution lithography at violet or ultraviolet(UV)wavelength,however,this has never been experimentally demonstrated.As a proof of concept,in this paper SCLs operating at 405 nm(h-line)wavelength with smaller full-width-at-half-maximum focal spot and longer depth of focus than conventional Fresnel zone lens while maintaining controlled side lobes are designed for direct laser writing(DLW)lithography.Aluminum nitride(AlN)with a high refractive index and low loss in UVvisible range is used to fabricate nanopillar-based metasurfaces structure for the metalens.Grating arrays with improved pitch resolution are fabricated using the SCLs with sub-diffraction-limit focusing capability.The AlN-based metasurface for SCLs at short wavelength for DLW could extend further to UV or deep UV lithography and might be of great interest to both the research and industry applications.

关 键 词：metalens direct laser writing supercritical lens diffraction limit ultraviolet metasurface 

分 类 号：TH74[机械工程—光学工程] TN249[机械工程—仪器科学与技术]