Subdiffraction focusing lens based on quadrangular-frustum pyramid-shaped metasurface Li, Huaixin ; Zhang, Qi ; Jiang, Xue ; Liang, Gaofeng ; Wen, Zhongquan ; Zhang, Zhihai ; Shang, Zhengguo ; Chen, Gang Abstract Publication: Applied Optics Pub Date: October 2019 DOI: 10.1364/AO.58.007688 Bibcode: 2019ApOpt..58.7688L