Compared with the conventional electron beam lithography (EBL) technology, direct laser writing (DLW), emerging as a powerful fabrication tool to realize three-dimensional (3D) micro/nanostructures, has demonstrated its superiorities in noncontact, cost effectiveness, mask-free characteristic, and diverse-substrate compatibility with various materials. Treated as an optical module, DLW can be easily integrated into 3D printing, bio printing and nanoimprint techniques, and hence this joint system could conceptually promote a brand new type of fabrication facility, namely the so called “versatile nanofabricationer” (VNFer). However, DLW suffers from relatively low accuracy and resolution owing to the optical diffraction limit which severely prevents fabricating fine structures with feature sizes in nanoscale. In our lab, an emerging DLW technique inspired by optical superresolution nanoscopy is demonstrated for realizing 3D nanostructures. A super-resolved feature in deep sub-wavelength scale can be achieved by employing a two-beam optical superresolution approach which is highly required in next-generation 3D integrated nanodevices.
Apart from achieving 3D complex nanostructures, one of the other crucial applications resorting to the two-beam superresolution approach is ultrahigh-density data storage. With this approach, 9 nm in line width and 33 nm in spot size which are far beyond the diffraction limit are realized. These outcomes possess the potential to disrupt the current high-density storage techniques, such as Blu-ray technique, and facilitate an ultraphotonic-disc (UPD) data storage scheme. On the other hand, expanding the storage dimensions provides another promising approach for increasing the density of data storage. Wavelength, polarization, and orbital angular momentum, all of which are the basic properties of light, are purposefully investigated, studied, and compacted to the traditional 3D volume data storage. With these new-type multiplexing approaches and the novel recording media (gold nanorods, metasurfaces, opto-magnetic materials, etc.), we have enriched the storage mode and quintupled the density of nowadays data storage, which would be further enhanced in the near future.