UV-assisted NIL integration of dielectric metalenses for devices: enhanced structural robustness and off-axis performance.

Metalenses are ultrathin optical components enabling precise wavefront control via the use of engineered nanostructures and are traditionally fabricated as standalone elements. Herein, we demonstrated their integration with other optical components, particularly a distributed Bragg reflector mirror structure. Using nanoimprint lithography (NIL), we fabricated a metalens with a numerical aperture of 0.6, lens diameter of 300 µm, and focal length of 200 µm. By redesigning the metalens structure, we overcame challenges associated with using silicon as the master mold in NIL, ensuring high-fidelity pattern transfer and scalable fabrication. Additionally, we investigated the impact of various fabrication errors (mostly specific to the redesigned unit cell geometry) on the focusing efficiency of the metalens. The optimized design enhanced off-axis performance at visible wavelengths, and we validated the robustness of such metasurfaces for complex optical applications. Successful metalens integration with other optical devices demonstrated the industrial feasibility of the proposed approach, paving the way for advanced imaging and electromagnetic wave manipulation applications.