High-Speed Micron-Scale 3D Printing Using Resonant-Scanning Two-Photon Microscopy

Pearre BW, Michas C, Tsang JM, Gardner TJ, Otchy TM. Fast micron-scale 3D printing with a resonant-scanning two-photon microscope. Addit Manuf 2019;30:100887. doi: 10.1016/j.addma.2019.100887.

Background: Three-dimensional (3D) printing through direct laser writing (DLW) enables fabrication of microstructures by polymerizing light-sensitive materials with a focused femtosecond laser. However, conventional DLW systems are limited by slow scanning speeds, typically using galvanometer mirrors or translation stages that restrict object size and throughput. The study aimed to overcome these limitations by introducing a resonant-scanning two-photon microscope for faster, micron-scale 3D printing while maintaining high resolution and accessibility through open-source software.

Hypothesis: This study hypothesized that integrating a resonant mirror scanner into a two-photon microscope could greatly increase printing speed without compromising micron-level resolution, thereby enabling rapid and affordable fabrication of small-scale 3D objects.

Methods: The authors constructed a raster-scanning direct laser writing system based on a commercial two-photon microscope equipped with a resonant and galvanometer scanner, femtosecond laser and Pockels cell for laser modulation. The system was controlled using ScanImage with a custom MATLAB application, PrintImage, for voxelization and laser power control. Calibration, accuracy and resolution were validated through printed rulers and microstructures fabricated in IP-Dip and Ormocomp photoresists.

Results: The resonant-scanning system achieved printing speeds of 3.3 m/s and fabricated 400 × 400 × 350 μm objects within approximately 25 seconds – about ten times faster than galvanometer-based systems. Dimensional errors were below 2.5%, and minimum feature sizes reached 1–2 μm along the X-axis and 0.3–0.5 μm along Y and Z.

Conclusions: The study demonstrated that resonant scanning enables fast, accurate, and accessible micron-scale 3D printing. The open-source system expands the capabilities of two-photon microscopes and provides a platform for future high-speed additive manufacturing innovations.