Meta‐Dispersive 3D Chromatic Confocal Measurement

Abstract 3D reconstruction can perceive the detailed structures of real‐world objects. Integrating metasurfaces with stereo vision or structured‐light projection enables compact and efficient 3D reconstruction systems, beneficial for next‐generation sensing, augmented reality, and biomedical applications. Nevertheless, the limitations inherent in these visual measurement methods pose a significant challenge to achieving higher resolution. Here, a dispersive metalens (DML) combined with the chromatic confocal method is proposed to achieve high‐precision 3D measurement. With appropriate engineered dispersion, the linearity of the dispersion is well maintained, alongside diffraction‐limited focusing performance. As a proof‐of‐concept, experiments on both longitudinal and transversal measurements are conducted. Following the calibration of the DML, axial accuracy of ±4 µm and a subwavelength axial resolution of 0.325 µm is achieved. The successful reconstruction of a fabricated 3D USAF‐1951 resolution test chart further corroborates the 3D measurement capability, demonstrating a lateral resolution exceeding 4.38 µm. It is envisioned that the proposed method will pave the way for future applications in areas such as microstructure characterization, industrial inspection, and on‐chip 3D optical metrology.