Nonlinear Photon Sieves for High‐Fidelity Wavefront Engineering

Abstract Domain‐engineered nonlinear photonic crystals have long served as versatile platforms for structured light modulation, leveraging spatially dependent nonlinearity to control the wavefronts of nonlinear interacting waves. However, most of these crystals rely on classical nonlinear holography, which is limited to unidirectional light field reconstruction and suffers from mode degradation caused by fabrication imperfections, such as lateral domain diffusion. Here, nonlinear photon sieves that replace the stripe‐like patterns with discrete dot‐array structures are introduced. This design not only exhibits high noise resistance but also enables multidimensional, high‐fidelity modulation of nonlinear structured light. This experiments demonstrate the nonlinear generation of Airy beams, higher‐order Laguerre–Gaussian beams, Hermite–Gaussian beams, and Ince–Gaussian beams across a broadband spectrum from 450 to 650 nm. This approach provides a robust, multidimensional platform for the development of domain‐engineered nonlinear photonic crystals, opening new avenues for advanced optical modulation and computation.