Rapid Two-Photon Polymerization of an Arbitrary 3D Microstructure with 3D Focal Field Engineering.

Two-photon polymerization is a powerful method for three-dimensional (3D) precision nanofabrication. To facilitate the fabrication speed, for the first time, single-exposure or single-scan two-photon polymerization of an arbitrary 3D microstructure with smaller or larger volume is demonstrated through focal field engineering. The constraints and the initial conditions of the Gerchberg-Saxton algorithm for the retrieval of the incident wavefront are adapted for the shape fidelity and the smoothness of the 3D focal field intensity distribution. As a result, a small 3D microstructure can be polymerized by a single exposure within 0.1 s, while a larger one can be formed by continuous polymerization of slices of the structure with one-dimensional single scan with a speed of 6 µm s-1 . The microlenses that generate vortex beams with different orbital angular momentums are polymerized to demonstrate the high fabrication precision. These pave the way for the rapid two-photon polymerization of arbitrary 3D structures.