Going far beyond the near-field diffraction limit via plasmonic cavity lens with high spatial frequency spectrum off-axis illumination

• DOI: 10.1038/srep15320
• Publication Date: 2015-10-19T09:39:19Z
• Authors: Zeyu Zhao; Yunfei Luo; Wei Zhang; Changtao Wang; Ping Gao; Yanqin Wang; Mingbo Pu; Na Yao; Chengwei Zhao; Xiangang Luo
• Keywords: Superlens; Plasmonic lens; Photoresist

For near-field imaging optics, minimum resolvable feature size is highly constrained by the diffraction limit associated with illumination light wavelength and air distance between devices objects. In this study, a plasmonic cavity lens composed of Ag-photoresist-Ag form incorporating high spatial frequency spectrum off-axis (OAI) proposed to realize deep subwavelength far beyond limit. This approach benefits from resonance effect wavevector shifting behavior via OAI, which remarkably enhances object's information damps negative contribution longitudinal electric field component in region. Experimental images well resolved 60-nm half-pitch patterns under 365-nm ultra-violet are demonstrated at 80 nm mask lens, approximately four-fold longer than that conventional lithography superlens scheme. The ultimate for object could be theoretically extended 120 nm. Moreover, two-dimensional L-shape illustrated simulations experiments. study promises significant potential make as practical, cost-effective, simple parallel nano-fabrication approach.