摘要
Nanophotonic platforms such as metasurfaces,achieving arbitrary phase profiles within ultrathin thickness,emerge as miniaturized,ultracompact and kaleidoscopic optical vortex generators.However,it is often required to segment or interleave independent sub-array metasurfaces to multiplex optical vortices in a single nano-device,which in turn affects the device’s compactness and channel capacity.Here,inspired by phyllotaxis patterns in pine cones and sunflowers,we theoretically prove and experimentally report that multiple optical vortices can be produced in a single compact phyllotaxis nanosieve,both in free space and on a chip,where one meta-atom may contribute to many vortices simultaneously.The time-resolved dynamics of on-chip interference wavefronts between multiple plasmonic vortices was revealed by ultrafast time-resolved photoemission electron microscopy.Our nature-inspired optical vortex generator would facilitate various vortex-related optical applications,including structured wavefront shaping,free-space and plasmonic vortices,and high-capacity information metaphotonics.
基金
supported by the National Research Foundation,Prime Minister’s Office,Singapore under Competitive Research Program Award NRF-CRP22-2019-0006
the grant(R-261-518-004-720)from Advanced Research and Technology Innovation Centre(ARTIC)
the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-Project-ID 278162697-SFB 1242
ERC Advanced Grant Complex Plan,BMBF,DFG and BW-Stiftung
the Research Grants Council of Hong Kong(CRF Grant No.C6013-18G)
the City University of Hong Kong(Project No.9610434)
the support from A*STAR under its AME YIRG Grant(Award No.A2084c0172).
