Resin‐Imprinted Metasurfaces With Dumbbell Resonances in the Visible

ABSTRACT The development of optical metasurfaces has primarily focused on nanoresonators with sufficiently refractive indices, often requiring high‐aspect‐ratio structures or complex geometries to achieve full phase modulation under phase‐design principles. While nanoimprint lithography has attracted considerable attention for its high throughput and large‐area fabrication capability, conventional approaches typically rely on pattern transfer into hard masks followed by dry etching to realize high‐aspect‐ratio nanoresonators. Here, we introduce a newly developed dumbbell resonance that enables a direct nanoimprinting strategy for fabricating optical metasurfaces composed of resin‐based resonators (n ≈ 1.9) with a structural height of only 250 nm, thereby eliminating the need for high‐aspect‐ratio geometries or additional etching steps. Leveraging this concept, we realize complex vortex‐structured light, vivid structural colors, and diffraction‐limited flat lenses for imaging. These results establish dumbbell resonances as a versatile platform for low‐cost, large‐area, and multifunctional metasurfaces composed of low‐index, small–aspect‐ratio elements.