Method for designing a magic mirror system with a metalens

This paper introduces a design method for a Magic Mirror inspection system by incorporating a dielectric metalens to replace the conventional refractive relay lens group, thereby addressing the prevalent assembly errors and optical path redundancy. Optimized for narrowband illumination centered at 550nm, the metalens achieves full 0-2π phase coverage to facilitate rigorous system-level optical performance. Through rigorous coupled-wave analysis (RCWA) and ray-tracing synergy, the metalens-integrated system achieves a near-diffraction-limited performance, suppressing the on-axis RMS wavefront error to below 0.2λ and maintaining a highly comparable modulation transfer function (MTF) to traditional multi-element systems. Furthermore, compared to the conventional double-Gauss relay, which exhibits severe tolerance degradation (mean RMS wavefront error degrading to ∼3.4λ under Q1-level assembly errors), the monolithic metalens completely eliminates inter-element alignment errors. This approach offers a highly compact, robust, and alignment-free solution, improving the reliability of subsurface defect detection in applications utilizing narrowband illumination, such as semiconductor wafer inspection.