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Marco Astarita

Publications and source records attributed to Marco Astarita.

3 recordsLinked to original sources

Iterative approach for high-quality binary intensity hologram generation in augmented reality applications

Binary amplitude spatial light modulators, such as digital micromirror devices (DMDs), are increasingly relevant for computer generated holography due to their high refresh rates, low cost, and due to the emergence of subwavelength pixel architectures. However, the binary constraint limits the reconstruction quality, as conventional approaches rely on a binarization applied as a final step after hologram computation which leads to reduced efficiency and contrast. We introduce an iterative estimation approach for the generation of off axis binary amplitude holograms, in which the binarization constraint is applied at each iteration. We validate the approach through numerical simulations and experimental reconstruction using a DMD based optical setup. Quantitative and qualitative comparisons with random superposition and Gerchberg Saxton methods demonstrate significant improvements in image contrast, light efficiency, and reconstruction fidelity, with comparable computational cost. The proposed method provides a practical route toward high quality CGH using binary modulators and supports emerging applications requiring high speed and high resolution holographic projection.

physics.optics↗

Zero-Order Diffraction Suppression in Full Field-of-View Computer Generated Holography: A Camera In the Loop Interferometric Approach

We introduce a novel interferometric approach for suppressing zero-order diffraction (ZOD) in phase-only computer-generated holography. The technique relies on the destructive interference between the zeroth-order light and a suppression beam in a plane optically conjugated to the spatial light modulator (SLM). A camera-in-the-loop (CITL) calibration procedure retrieves the optimal pixel-wise phase map that cancels out the ZOD component with high precision, while preserving the full modulation depth of the SLM. Experimental demonstrations on point-cloud and 2D/3D holograms achieve up to 99% suppression of the ZOD intensity, without loss of image quality or field of view. Once calibrated, the correction can be applied to any hologram without recomputation, enabling real-time operation and robust performance over time. This method removes a long-standing barrier to the practical deployment of full-field holography, facilitating the development of compact, high-fidelity holographic engines for augmented and mixed reality displays.

physics.optics↗

Reprogrammable holograms from maskless surface photo-morphing

Holographic technologies have the potentiality to impact our everyday life in many sectors including science, education, entertainment, art, and healthcare. Although holographic screens and projectors are part of common imagination since long time, they are still at initial stages of development and integration. Recent achievements of metasurface and flat optics research gave an unprecedented strength to this field, overcoming critical aspects as efficiency, size and flexibility of conventional optics and liquid crystal technologies. However, although diffractive and metasurface holographic projectors with advanced functionalities and improved efficiencies are continuously reported, they are static devices, requiring demanding, burdensome, and irreversible manufacturing processes. Here we report an all-optical and single-step lithographic framework for the fabrication of diffractive holographic projectors directly on the surface of a photo-morphable polymer film. Real-time optimization during the accurate surface patterning and fully structural reconfigurability allowed for the first prototype of a fully reprogrammable pixel-less morphological projector, opening new routes for holographic image displaying and optical data sharing.

physics.optics↗