3D nanoscale fabrication and imaging: a multimodal approach for in situ and super-resolution characterization

The synergistic innovation of nanoscale optical fabrication and characterization technologies holds the key to overcoming three-dimensional (3D) precision manufacturing bottlenecks. This study reports the novel self-reporting functionality of 7-diethylamino-3-thenoylcoumarin (DETC) in photoresist, which serves as both a super-resolution photoinitiator and an intrinsic fluorophore with stimulated emission depletion (STED) behavior and polymerization-dependent lifetime characteristics. Through the development of an integrated system combining STED-inspired periphery photoinhibition (PPI) printing with dual-mode imaging, we achieve simultaneous in situ characterization and super-resolution quality verification. Specifically, PPI imaging demonstrates 50-nm lateral resolution for 40-nm printed lines and resolves 200-nm axial gaps when characterizing developed structures. Furthermore, in situ fluorescence lifetime imaging (FLIM) achieves nanometer-level resolution, comparable to confocal microscopy, by utilizing DETC’s lifetime shift to characterize undeveloped structures. This synergy imaging approach resolves the trade-off between resolution and non-destructive detection, while establishing a new paradigm for closed-loop optimization of complex 3D nanodevices, with profound implications for nanophotonics, precision biosensing, and ultrahigh-density optical storage.