Xianfan Xu1
Purdue University1
Two-photon lithography has become the dominant fabrication process for 3D nanoprinting for most applications today due to its capability to produce submicron features and true 3D printing of arbitrary structures. Still, the printing rate is often considered slow. Multiple methods have been proposed for improving two-photon 3D nanoprinting rates. Here, a rapid, continuous, layer-by-layer projection two-photon lithography process is described. To achieve 3D printing with submicron feature sizes, a spatiotemporal focusing effect due to a digital micromirror device (DMD) projection system applied to the femtosecond printing laser pulses confines the polymerization region of the photoresist to a thin 2D plane. By continuously changing the projected DMD pattern without pauses in printing layers while varying the height of the print plane in the photoresin, smooth 3D prints are achieved rapidly. Millimeter scale printing is demonstrated by printing various complex 3D geometries. This presentation will also discuss recent progresses toward grayscale printing, real time imaging and feedback, multiple beam printing, and machine learning to improve the speed and accuracy of 3D nanoprinting.