Multi-wavelength encoded holography with independent Fresnel diffraction modulation

Multi-wavelength encoded holography establishes a transformative framework for high-capacity data storage and broadband optical displays by leveraging its wavelength independence to encode spatial information of multiple images. However, conventional supercell-based approaches confront persistent limitations in scaling holographic channel capacity and optimizing energy efficiency, thereby impeding advancements in optical holography. To overcome these challenges, we present a novel paradigm for multi-wavelength encoded holography that decouples holographic information via independent Fresnel diffraction modulation. By introducing the wavelength-dependent dynamics inherent to Fresnel diffraction of light waves in free space, a linear spectral-spatial mapping can be established, thereby enabling multi-wavelength holographic reconstruction through near-field phase modulation. In proof-of-concept experiments, we successfully implemented 3-channel and 6-channel wavelength-encoded holography using fabricated planar photonic devices. The results demonstrated an effective energy ratio of each reconstructed hologram exceeding 85.3 % and a minimum crosstalk approaching −13.67 dB. This work provides a promising solution for enhancing holographic channel capacity within the wavelength domain, with advantages of extended response bandwidth and improved energy efficiency. These findings may offer new insights for the development of advanced optical holography.