The in-plane negative refraction of high-momentum(i.e.,high-k)photonic modes could enable many applications such as imaging,focusing,and waveguiding in a planar platform at deep-subwavelength scales.However,its practi...The in-plane negative refraction of high-momentum(i.e.,high-k)photonic modes could enable many applications such as imaging,focusing,and waveguiding in a planar platform at deep-subwavelength scales.However,its practical implementation in experiments remains elusive so far.Here we propose a class of hyperbolic metasurfaces,which is characterized by an anisotropic magnetic sheet conductivity and can support the in-plane ultrahigh-k magnetic designer polaritons.Based on such metasurfaces,we report the experimental observation of the all-angle negative refraction of designer polaritons at extremely deep-subwavelength scales.Moreover,we directly visualize the designer polaritons with hyperbolic dispersions.Importantly,for these hyperbolic polaritons,we find that their squeezing factor is ultra-large.To be specific,it can be up to 129 in the experiments,an ultra-high value exceeding those in naturally hyperbolic materials.This work may pave a way toward exploring the extremely high confinement and unusual propagation of magnetic designer polaritons over monolayer or twisted bilayer hyperbolic metasurfaces.展开更多
基金National Natural Science Foundation of China(61625502,61975176,11961141010)Top-Notch Young Talents Program of China+2 种基金Fundamental Research Funds for the Central UniversitiesMinistry of Education-Singapore(MOE2015-T2-1-070,MOE2016-T3-1-006,MOE2018-T2-1-022(S)Tier 1 RG174/16(S))。
文摘The in-plane negative refraction of high-momentum(i.e.,high-k)photonic modes could enable many applications such as imaging,focusing,and waveguiding in a planar platform at deep-subwavelength scales.However,its practical implementation in experiments remains elusive so far.Here we propose a class of hyperbolic metasurfaces,which is characterized by an anisotropic magnetic sheet conductivity and can support the in-plane ultrahigh-k magnetic designer polaritons.Based on such metasurfaces,we report the experimental observation of the all-angle negative refraction of designer polaritons at extremely deep-subwavelength scales.Moreover,we directly visualize the designer polaritons with hyperbolic dispersions.Importantly,for these hyperbolic polaritons,we find that their squeezing factor is ultra-large.To be specific,it can be up to 129 in the experiments,an ultra-high value exceeding those in naturally hyperbolic materials.This work may pave a way toward exploring the extremely high confinement and unusual propagation of magnetic designer polaritons over monolayer or twisted bilayer hyperbolic metasurfaces.
