Tomographic Volumetric Additive Manufacturing by Holographic Projections

Different Light-based techniques for 3D printing have been developed such as SLA and DLP thatuse single photon absorption and direct writing by scanning a focused spot using two photon absorption.These techniques employ a layered approach using incoherent imaging. Herein, we propose a layerlessapproach using coherent holographic projection which is based on Tomographic Volumetric AdditiveManufacturing (TVAM). We demonstrated this concept by implementing a volumetric printer using a DigitalMicromirror Device (DMD) in a Fourier configuration and showing its capabilities by printing a micrometricscale object. The use of the Lee holograms method allows us to use the DMD as a fast phase modulator, andthe combination of tiling holograms with Point Spread Function (PSF) modifications allows us to reducespeckle noise and provide three-dimensional control of the projections. We use these holographic projectionsto fabricate millimetric 3D objects in less than a minute.