Wan-Ping Guo et al.MINN-TSONG LIN2021-07-282021-07-28202015306984https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083002784&doi=10.1021%2facs.nanolett.0c00645&partnerID=40&md5=36fc1cf862da3b919ee577bfbd82190ehttps://scholars.lib.ntu.edu.tw/handle/123456789/573751Two-dimensional spiral plasmonic structures have emerged as a versatile approach to generate near-field vortex fields with tunable topological charges. We demonstrate here a far-field approach to observe the chiral second-harmonic generation (SHG) at designated visible wavelengths from a single plasmonic vortex metalens. This metalens comprises an Archimedean spiral slit fabricated on atomically flat aluminum epitaxial film, which allows for precise tuning of plasmonic resonances and subsequent transfer of two-dimensional materials on top of the spiral slit. The nonlinear optical measurements show a giant SHG circular dichroism. Furthermore, we have achieved an enhanced chiral SHG conversion efficiency (about an order of magnitude greater than the bare aluminum lens) from monolayer tungsten disulfide (WS2)/aluminum metalens, which is designed at the C-exciton resonance of WS2. Since the C-exciton is not a valley exciton, the enhanced chiral SHG in this hybrid system originates from the plasmonic vortex field-enhanced SHG under the optical spin-orbit interaction. Copyright ? 2020 American Chemical Society.Aluminum; Dichroism; Epitaxial films; Excitons; Hybrid systems; Monolayers; Nonlinear optics; Optical data processing; Plasmonics; Spin orbit coupling; Sulfur compounds; Tungsten compounds; Vortex flow; Archimedean spiral; Exciton resonances; Non-linear optical; Plasmonic resonances; Topological charges; Tungsten disulfide; Two-dimensional materials; Visible wavelengths; Harmonic generationjournal article10.1021/acs.nanolett.0c00645321632912-s2.0-85083002784