High-Repetition-Rate Projection Multiphoton Lithography for Large-Area Sub-Micron 3D Printing

TL;DR

High-resolution MPL is limited by low volumetric throughput for 3D metasurfaces. This work introduces a holographic projection lithography platform that combines spatiotemporal beam shaping, a DMD-based diffractive projection, and simultaneous spatiotemporal focusing to achieve axial confinement and large-area printing. Under optimized resin chemistry (Irgacure 369) and a pulse compressor delivering pulses <60 fs at repetition rates up to 500 kHz, the system achieves sub-400 nm lateral resolution and throughput up to 2.3e6 voxels/s, demonstrated on micropillar arrays and woodpile lattices. The approach enables scalable, industrially relevant micro-optical component manufacturing by stitching large areas with uniform voxel polymerization while avoiding thermal effects and hatching artifacts.

Abstract

High-resolution lithographic techniques are often limited by low volumetric throughput, since there is no universal and scalable manufacturing process that can produce 3D metasurfaces. In this work, we demonstrate a high-speed holographic 3D printing platform based on spatiotemporal beam shaping, exceeding the repetition rate while keeping the resolution high. The system integrates a femtosecond laser source with a spectral pulse compressor and a beam shaper to project uniform, axially confined light fields to project patterns directly on the advanced photoresists using a Digital Micromirror Device DMD. We investigate the process window for rapid polymerization, optimizing the photoinitiator choice to eliminate thermal crosstalk at high repetition rates. Using this setup, we achieve a production throughput of more than a million voxels per second with sub-micron resolution below 400 nm. The system's reliability is validated through the fabrication of large-area woodpile-like lattices and uniform micropillar arrays, establishing a workflow for scalable manufacturing of micro-optical components.

Figures (9)

• Figure 1: Schematic of the integrated optical system showing the laser source, pulse compression module, SHG, and the spatiotemporal beam shaping path.
• Figure 2: Comparison of spectral analysis before and after the compressor module (left), and quality of the profile of the laser beam accordingly (right).
• Figure 3: Top-hat beam profile after the $\pi$-shaper (left), and normalized intensity highlighting the output diameter of the beam and the uniformity of the intensity (right).
• Figure 4: Schematic presentation of the 4f configuration system after the DMD, where the temporal focusing is highlighted.
• Figure 5: SEM and microscope images of micropillars arrays fabricated employing DMD and spatiotemporal beam shaping, showing the impact of the photoinitiator in the fabrication process with BIS (left) and IRG369 (right).