As AI Vision systems shrink, traditional refractive lenses—which rely on bulk material curvature to bend light—are hitting physical and integration limits. The transition to Flat Optics allows for high-performance sensing in a fraction of the Z-height. To navigate this shift, engineers must distinguish between two primary technologies: Diffractive Optical Elements (DOE) and Metalenses. Diffractive Optical Elements (DOE): Micro-Scale Precision DOE technology has been the indus