Inverse design of a binary aperture for tailoring wavelength-multiplexed diffraction images.

Diffractive optical elements have emerged as powerful tools for compact and versatile wavefront manipulation. Binary apertures offer remarkable advantages in fabrication simplicity and broadband compatibility. However, the generation of wavelength-multiplexed diffraction images via a single binary aperture remains challenging. Here, we present an inverse design framework assisted with 3D optimal accumulation algorithm (3D-OAA) to tailor arbitrary 3D wavelength-multiplexed diffraction images via a single binary aperture. Leveraging the intrinsic spectral orthogonality of polychromatic diffraction intensities through a shared binary aperture, our method enables independent and simultaneous wavefront control across multiple wavelengths. As a proof of concept, we achieve the generation of high-quality wavelength-multiplexed diffraction images with fidelity exceeding 0.94 for 2D images and 0.85 for 3D images in simulations. Furthermore, dynamic reconstruction of eight groups of distinct color three-letter words at three planes is achieved via wavelength-selective multiplexing through a single binary aperture. Our work establishes a general methodology for multi-functional diffractive optics and offers promising applications in information coding, data storage, optical encryption, and color display.