A lithography-free approach to polaritonic Luneburg lenses.

ABSTRACT: Planar polaritonic lenses, achieved by precisely controlling interface polaritons, hold significant promise for subwavelength light focusing. While most existing designs rely on polariton interference or refraction, creating gradient-index polaritonic lenses remains a substantial challenge due to the lack of practical and cost-effective fabrication methods. Here, we introduce a lithography-free approach for producing polaritonic lenses with gradient effective refractive indices by engineering the dielectric environment of polaritons. This method involves in situ transformation of polymer microspheres into spherical caps through controlled melting, allowing the fabrication of polaritonic Luneburg lenses with focal spots as small as λ0/18, where λ0 is the free-space wavelength. Our approach

SUBMITTER: Cui Z 

PROVIDER: S-EPMC12368153 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature