July 24, 2026
By Tracie Troha

Researchers at the George W. Woodruff School of Mechanical Engineering have developed a new approach to nanoscale 3D printing that improves both speed and fidelity, overcoming a challenge that has limited the technology's broader use in manufacturing.

Their work, led by Sourabh Saha, associate professor and Woodruff Faculty Fellow, and Harnjoo Kim, who conducted the research during his doctoral studies and later as a postdoctoral fellow in Saha's lab, was recently published in the journal Nature Communications.

Nanoscale 3D printing allows researchers to create structures thousands of times smaller than the width of a human hair. These structures have potential applications in fields ranging from advanced computing and optics to biomedical devices and clean energy technologies. However, increasing printing speed often comes at the expense of quality.

"Many nanoscale 3D printing methods can produce very precise structures, but they are too slow for practical production," Kim said. "On the other hand, high-speed approaches often lose accuracy because it becomes difficult to control the printing process."

Several years ago, Saha's research group demonstrated a way to dramatically increase printing speed by processing entire planes of material at once rather than printing one point at a time. While that approach accelerated manufacturing, maintaining precise control over the amount of light delivered to different areas of a structure remained a challenge.

“When you process one point at a time, it is easy to control the light dosage,” Saha said. “However, when multiple points in a plane are processed at once, it becomes challenging. As light dosage must be controlled to produce accurate prints, we had no good way to independently control dosage at various spots within the plane.”

To solve that challenge, Saha and Kim developed a motif-based approach. Rather than controlling an entire light pattern at once, they build it from many small, carefully designed elements, similar to how an artist creates a painting with deliberate brushstrokes.

“Our approach keeps things simple by assembling the final pattern from many small, predictable pieces that are more like deliberate brushstrokes than a single wild splash,” Saha said.

The technique uses a device that can only turn pixels on and off. Conventional thinking suggests that such a system can create only two levels of light intensity. The team found a way to produce many intensity levels by arranging on-and-off pixels into precise patterns.

The breakthrough relies on diffraction, a fundamental property of light that typically limits how tightly light can be focused. Rather than treating diffraction as an obstacle, the researchers turned it into an advantage.

"Often, the diffraction limit is considered a nuisance," Saha said. "For us, it became an enabler."

By carefully designing patterns smaller than the diffraction limit, the team was able to precisely control how much light reached different parts of the printing area while maintaining a consistent spot size. The result was more accurate printing without sacrificing speed.