Lensless and Lossless HoloVAM

TL;DR

The paper presents the first demonstration of lensless holographic volumetric additive manufacturing (HoloVAM), delivering tomographic light fields directly into a rotating resin vial without imaging optics. By using a phase-only spatial light modulator and HoloTile PSF shaping, the system achieves axially extended beams and centimeter-scale 3D fabrication in under 30 seconds with high photon efficiency. The authors detail a computational pipeline for projection optimization and a minimal optical setup, along with a resin formulation suitable for rapid curing. The work establishes lensless HoloVAM as a compact, power-efficient platform with potential applications in biofabrication, medical components, and space-conscious manufacturing, while outlining clear avenues for performance enhancements and closed-loop corrections.

Abstract

We report the first successful fabrication of three-dimensional models using our fully lensless holographic volumetric additive manufacturing (HoloVAM) platform. In this configuration, tomographic light fields are generated directly from a phase-only spatial light modulator (SLM) and delivered into a rotating vial of photopolymer without any imaging optics, relays, or index-matching bath. Building on the HoloTile framework for tiled Fourier holography and point-spread function (PSF) shaping, the system creates volumetric dose distributions with high photon efficiency and well-controlled axial propagation. Using a simple acrylate resin formulation and a minimalized optical train, we demonstrate reproducible fabrication of complex geometries. These results establish lensless HoloVAM as a practical and mechanically minimal route to volumetric fabrication, opening a new pathway toward compact and application-flexible VAM devices.

Figures (3)

• Figure 1: Conceptual illustration of the lensless HoloVAM principle. A phase-only SLM is illuminated by an expanded and collimated laser beam. The SLM modulates the wavefront, allowing the necessary projection patterns to form due to the free-space propagation between the SLM and the vial in which a model is cured. A linear polarizer is inserted following the SLM to ensure the passage of only SLM-modulated light. Illustration credit: Sammy Florczak bernal_road_2025zandrini_breaking_2023.
• Figure 2: Lensless HoloVAM projection setup used for volumetric fabrication experiments. A single-mode 405 nm fiber-coupled diode laser is expanded onto a phase-only spatial light modulator, housed in a compact enclosure. The SLM encodes HoloTile holograms that generate axially extended Bessel-like beams, which propagate directly into a rotating cylindrical resin vial. A monitoring camera positioned off-axis to the vial captures the curing process (grayscale inset).
• Figure 3: Computational and optical workflow of the lensless HoloVAM system. Target meshes are voxelized and converted to angular projections, which are pre-warped for cylindrical refraction and refined through an iterative dose-based optimization. Each corrected projection is converted to a phase-only HoloTile hologram containing both tiling, PSF shaping, and the digitally applied lens phase. The holograms are displayed on the SLM in sync with vial rotation, and, after polarization filtering, propagate freely to form the three-dimensional exposure field directly inside the resin-filled vial.