LLNL has been at the forefront in developing two-photon polymerization (TPP) additive manufacturing (AM) method. In 2018, LLNL was a recipient of a Federal Laboratory Consortium (FLC) award for their development of FemtoProWrite, which leverages TPP. TPP is a laser light-directed writing technique in which crosslinking reactions initiated by light lead to a change from liquid to solid within a region that is smaller than the light spot. The method is very high resolution, capable of fabricating micro- and nano-scale features.
However, conventional TPP AM printers have extremely slow printing speeds with limited part size since they utilize a single laser spot approach where the laser is directed through a conventional microscope objective and the 3D printed part is built by scanning within the resin material. There is a market need to maintain the high sub-micron printing resolution offered by TPP, while increasing the throughput and dimensions of the printed components.
LLNL researchers have developed a parallelized TPP system that combines metalens array and spatial light modulator (SLM) to manipulate the directed laser light, which enables high-volume fabrication of nano-architected structures at wafer-scale. Instead of using a single microscope objective, LLNL’s approach uses an array of metalens that the laser passes through with each metalens being independently controlled via a SLM. This parallelization of printing allows for large scale, high throughput writing of periodic and non-repeating patterns that exceed the capabilities of conventional TPP platforms. This novel approach significantly increases throughput without sacrificing resolution or introducing stitching errors.
Image Caption: Metalens Array used for massively parallel Two-Photon Polymerization (TPP)
Current stage of technology development:
TRL ☐ 0-2 ☒ 3-5 ☐ 5-9
LLNL has filed for patent protection on this invention.
U.S. Patent Application No. 2022/0252761System and method for parallel two-photon lithography using a metalens array published 8/11/2022
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- 1000X speed compared to currently available TPP printers
- Wafer-scale
- 100 nm-resolution
- Free of stitching defects
Using the fine resolution of submicron AM, the technology can be used in a wide variety of fields to fabricate functional micro- and nanoscale 3D structures for photonic crystals, micro-optics, mechanical metamaterials, micro fluidics, miniaturized optics, flexible micro-electronics, Micro-electromechanical Systems (MEMS), on-demand 3D chip packaging solutions, custom micro-heatsinks for the next-generation semiconductor and high-density 3D optical memory. TPP can also be used to produce architected materials for energy solutions (e.g., battery and CO2 electrolyzer electrodes) and biomedical engineering (e.g., neural probes).
