Achromatic 3D Multi-Color Orbital Angular Momentum Holography

Orbital angular momentum (OAM) holography represents a transformative technique for enhancing the information channel capacity of holographic systems through the convolution of theoretical infinite OAM states with discrete sampling target images. However, the inherent axial chromatic aberration (ACA) in Fourier lens functions leads to the misalignment of Fourier planes for OAM-dependent holograms across different wavelengths, thereby limiting 3D multicolor OAM holography. To address this challenge, a novel approach achieving achromatic 3D multi-color OAM holography using a spatial multiplexing scheme is presented. Specifically, an optically digitalized achromatic OAM-dependent hologram is developed by superposing wavelength-specific lens functions onto monochromatic Fourier OAM-dependent holograms, followed by high-resolution spatial discretization and interleaving via two-photon lithography (TPL). Experimental results demonstrate that the method enables a double-plane (along the propagation direction of light), 3-color (633, 532, and 460 nm), and 3-channel OAM-multiplexing holographic display (OAM order l_en = 1,4, and 7) with the ACA correction, utilizing a nano-printed hologram featuring a subwavelength (600 nm) pixel size. This breakthrough paves the way for high-capacity, multi-spectral 3D holographic data storage and retrieval, with significant implications for augmented reality (AR)/virtual reality (VR) display, optical holographic encryption, and optical artificial intelligence.