Georgia Tech Researchers Print Nanoscale Objects a Thousand Times Faster

Researchers at Georgia Tech have developed a nanoscale 3D printing technique that can fabricate tiny structures a thousand times faster than conventional two-photon lithography without sacrificing resolution. The breakthrough uses a digital micromirror device that arranges pixels into precise patterns to control light intensity.

Traditional two-photon lithography builds objects by focusing a femtosecond laser into a photoresist, polymerizing material voxel by voxel. The process produces features below 200 nanometers, but it is painfully slow. Typical systems print at around 0.01 cubic millimeters per hour, which makes production of anything beyond microscopic samples impractical.

The Georgia Tech team, led by graduate student Saha, realized that the diffraction limit usually treated as a barrier can actually be harnessed. By designing pixel patterns smaller than the diffraction limit, they created many intensity levels from a binary on-off device. The result is a grayscale projection that shapes light across the build area while keeping a consistent spot size.

The new method, called grayscale projection two-photon lithography, maintains sub-diffraction feature sizes while projecting entire layers at once. That shift from point-by-point to layer-by-layer processing is what delivers the thousand-fold speed increase. The researchers demonstrated the technique by printing photonic crystals, micromechanical structures, and micro-optics with features below 200 nanometers.

The work has immediate implications for optical communications, biomedical devices, and metamaterials. The team plans to test new photoresists and push the process toward even larger build volumes.