Xolography for linear volumetric 3D printing


The range of applications for additive manufacturing is expanding quickly, including mass production of athletic footwear parts1, dental ceramics2 and aerospace components3 as well as fabrication of microfluidics4, medical devices5, and artificial organs6. The light-induced additive manufacturing techniques7 used are particularly successful owing to their high spatial and temporal control, but such techniques still share the common motifs of pointwise or layered generation, as do stereolithography8, laser powder bed fusion9, and continuous liquid interface production10 and its successors11,12. Volumetric 3D printing13,14,15,16,17,18,19,20 is the next step onward from sequential additive manufacturing methods. Here we introduce xolography, a dual colour technique using photoswitchable photoinitiators to induce local polymerization inside a confined monomer volume upon linear excitation by intersecting light beams of different wavelengths. We demonstrate this concept with a volumetric printer designed to generate three-dimensional objects with complex structural features as well as mechanical and optical functions. Compared to state-of-the-art volumetric printing methods, our technique has a resolution about ten times higher than computed axial lithography without feedback optimization, and a volume generation rate four to five orders of magnitude higher than two-photon photopolymerization. We expect this technology to transform rapid volumetric production for objects at the nanoscopic to macroscopic length scales.

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Fig. 1: Xolography 3D printing technology.
Fig. 2: Volumetric digital manufacturing.
Fig. 3: Characterization of high-resolution object features.

Data availability

The data that support the findings of this study are available within the paper and Supplementary Information. Additional supporting data generated during the present study are available from the corresponding authors upon reasonable request.


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We thank D. Radzinski for continuous support, F. Pinno and N. Wandel for SEM measurements, P. Fengler and A. F. Thünemann as well as J. Müller and A. Gurlo for help with material property measurements, S. Schneider and M. Dinter for 3D visualization of the printing zone, A. Steinbach for CAD modelling of the optical setup, and M. Vollmer for proofreading the manuscript.

Author information




M. Regehly and S.H. designed the research and wrote the paper. Y.G. designed the spiropyran photoinitiator. Synthesis and characterization was performed by Y.G. and M. Reuter. Theoretical work and simulations by M. Regehly. Volumetric printer development was done by M. Regehly, M. Reuter, D.P.K. and C.-Y.C. 3D data processing was done by M. Reuter, E.I. and M. Regehly. Development of resin formulations, characterization and post-processing were performed by N.F.K., E.I. and Y.G. Software development was done by K.K. and B.A.

Corresponding authors

Correspondence to Martin Regehly or Stefan Hecht.

Ethics declarations

Competing interests

Two patents (DE 10 2019 115 336 and DE 10 2019 129 868) have been filed related to the topic covered in this publication.

Additional information

Peer review information Nature thanks Cyrille Boyer, Robert McLeod and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Synthesis of DCPI.

MeI, methyl iodide (CH3I).

Extended Data Fig. 2 1H NMR (500 MHz, CDCl3) of DCPI


Extended Data Fig. 3 13C NMR (126 MHz, CDCl3) of DCPI


Extended Data Fig. 4 19F NMR (471 MHz, CDCl3) of DCPI


Extended Data Fig. 5 Optical design and characterization of the light sheet generator.

a, Schematic representation of the optical setup. L1, Powell lens. L2, L3, cylindrical lenses. S, beamsplitter. M, mirrors. A, linear axis. C, cuvette. b, Partial image of the light sheet in one arm at waist position. c, Horizontal lineout of the light sheet intensity distribution.

Extended Data Fig. 6 Results of the calibration procedure.

a, Diagram showing an array of tested irradiance/velocity combinations, which are used to identify the parameter space for xolography 3D printing. b, Photograph of the automated testing procedure in a 1-cm cuvette containing resin 1.

Extended Data Fig. 7 Optimal light sheet waist widths.

The plot shows the FWHM waist sizes dFWHM of the light sheet against volume depth D for different values of the homogeneity factor β. The simulation has been performed for the design wavelength of λ = 375 nm and assumed refractive index of the resin of n = 1.56 (375 nm).

Extended Data Fig. 8 Simulation of light sheet intensity distributions.

a, Exponential intensity decrease along the 1-cm volume depth for single-side illumination. b, Double-sided illumination leads to a nearly homogenous distribution for 1-cm depth. c, Maximum deviation from the average intensity in percentage for volume depths of up to 10 cm.

Extended Data Fig. 9 Mechanical characterization of printed and post-processed test specimen.

a, Stress–strain curve obtained at a nominal strain rate of 4 × 10−2 s−1. The inset shows the sample mounted to the holder of the tensile testing machine. b, Modulus-temperature behaviour acquired using a 1 K min−1 heating ramp rate and an amplitude of 30 µm at an oscillation frequency of 1 Hz. The inset shows the sample mounted to the stage of the dynamic mechanical analyser.

Supplementary information

Peer Review File

Video 1

: Xolography volumetric 3D printing. Video of the printing process in 1, 3 and 5 cm volume depth. Solidified objects are highly transparent and only visible via diffuse light scattering.

Video 2

: Function test of the printed flowcell. A simple example of multicomponent systems with mechanical functionalities made by volumetric 3D printing in one step without the need for subsequent assembly.

Video 3

| Stability demonstration of the anatomical model. If required, xolography creates objects with similar mechanical stability compared to conventional point-by-point or layer-by-layer production processes.

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Regehly, M., Garmshausen, Y., Reuter, M. et al. Xolography for linear volumetric 3D printing. Nature 588, 620–624 (2020). https://doi.org/10.1038/s41586-020-3029-7

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