Non-diffracting reconfigurable orbital angular momentum holography

Orbital angular momentum (OAM) holography exploits an unbounded set of orthogonal OAM states, in principle offering high information capacity for data storage and optical encryption. However, diffraction-induced degradation away from the focal plane restricts conventional OAM holography to a shallow depth of field, so high-fidelity reconstruction is achieved only near focus. Here, we demonstrate a propagation-stable OAM holography scheme based on angular-spectrum engineering. A specially designed annular mask constrains the output wavevectors to a conical geometry on the Ewald sphere, extending the usable depth of field from 0.8 cm (conventional OAM holography) to ∼40 cm. Within this reconfigurable framework, we prescribe an axially varying OAM modulation m(z) to enable stepwise longitudinal decoding of distinct images. We further demonstrate two-parameter addressing, in which multiplexed patterns are retrieved by a key pair consisting of the incident OAM state l_in and the selected axial segment, and the intended pattern is recovered only for the matching pair. Experimentally, the correctly addressed reconstructions achieve a structural similarity index measure (SSIM) exceeding 0.94 relative to the target patterns. These results establish a non-diffracting, reconfigurable OAM holography platform that offers a tunable depth of field and axial selectivity, with potential applications in optical encryption, displays, and high-capacity data storage.