A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several...A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several lenses that have different focal points into a planar integrated unit,resulting in low imaging quality because of the high background noise.Here we show that the defects of the traditional method can be overcome by designing a metalens with conic shapes(the ellipse and the hyperbola);this approach could improve the imaging performance and substantially decrease the background noise of multifocal metalenses.These benefits arise from the intrinsic properties of the two conic curves,which can focus incident light constructively at all of the foci of the metalens.We further demonstrate that the proposed conicshaped metalens can function well within a broadband operation wavelength that ranges from 600 to 900 nm with the dual polarity actively controlled by the incident circular polarized light.The great agreement between the experimental and simulation results demonstrates that our proposed metalens has significant potential for use in future integrated nanophotonic devices.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0206000)National Basic Research Program of China(973 Program,Grant No.2015CB932403,2017YFA0205700)+2 种基金the National Science Foundation of China(Grant No.61422501,11674012,11374023,61176120,61378059 and 61521004)the Foundation for the Author of the National Excellent Doctoral Dissertation of PR China(Grant No.201420)the National Program for Support of Top-notch Young Professionals.
文摘A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several lenses that have different focal points into a planar integrated unit,resulting in low imaging quality because of the high background noise.Here we show that the defects of the traditional method can be overcome by designing a metalens with conic shapes(the ellipse and the hyperbola);this approach could improve the imaging performance and substantially decrease the background noise of multifocal metalenses.These benefits arise from the intrinsic properties of the two conic curves,which can focus incident light constructively at all of the foci of the metalens.We further demonstrate that the proposed conicshaped metalens can function well within a broadband operation wavelength that ranges from 600 to 900 nm with the dual polarity actively controlled by the incident circular polarized light.The great agreement between the experimental and simulation results demonstrates that our proposed metalens has significant potential for use in future integrated nanophotonic devices.
