High‐Index, Low‐Loss Optical Material Platforms for Ultra‐Broadband Ultraviolet‐to‐Visible Achromatic Metalenses

ABSTRACT Achromatic metalenses offer a route toward compact and lightweight optical systems; however, extending broadband operation into the ultraviolet (UV) regime remains challenging because few materials simultaneously provide a high refractive index and low optical absorption. Here, we present a photonic platform for UV‐to‐visible achromatic operation using two complementary material strategies. First, low‐loss, high‐index SiNx thin films are engineered by controlling the N 2 flow rate during plasma‐enhanced chemical vapor deposition, enabling broadband achromatic metalenses operating from 320 to 450 nm with minimal focal shift and near‐diffraction‐limited performance. Second, to enable scalable fabrication, we implement a single‐step nanoimprint lithography process using ZrO 2 nanoparticle‐embedded resin (PER), which allows direct high‐index metasurface patterning without etching. Using this printable platform, we demonstrate an achromatic ZrO 2 PER metalens operating from 375 to 645 nm. By combining high‐performance UV meta‐optics with scalable nanoprinting, this work provides a practical pathway toward compact photonic systems supporting both visible imaging and UV‐based authentication within a single optical platform.