Nanofabrication techniques have significantly impelled the development of nanomechanics and nanophotonics by making nano‐precision material processing routine. Although widely employed, current sub‐100 nm nanofabrication approaches based on focused particles or light are limited to surface modification. Here, an optical in‐volume fabrication approach that enables 3D glass processing with a spatial resolution down to 40 nm is demonstrated. Such an approach is based on the formation of a single nanoslit structure induced by femtosecond laser pulses. Spatially‐variant nanopatterns with uniform line‐widths are then formed by a near‐field mediated intensity redistribution of incident light. The redistribution of electromagnetic field induced by the presence of the nanoslit leads to a positive‐feedback self‐assembly process. The self‐assembly process allows achieving spacing one order of magnitude smaller than the laser beam size. In addition, a tilted ablation front that results in the generation of structures with curved morphology is revealed. The proposed approach enables 3D patterning with a lateral spacing down to 200 nm and 5D optical data storage with an equivalent capacity of 7.2 TB per disk, demonstrating its feasibility for 3D nanoscale processing in bulk materials.

Herein, a flexible four-dimensional optical data storage technique is demonstrated by harnessing ultrafast laser-induced fluorophores in thermoplastic polyurethane. By modulating the pulse energy of a 515 nm laser, data voxels with multilevel fluorescence signals can be generated and encoded. The readout accuracy of the encoded multilayer information remains at 92.2% after 50 bending cycles, demonstrating the feasibility of our technology for data recording based on a roll-to-roll method. The generation of fluorophores by only a single femtosecond laser pulse provides the ability to record data beyond 20 MB/s.

Anisotropic nanostructures can be generated in fused silica glass by manipulating the spatiotemporal properties of a picosecond pulse. This phenomenon is attributed to laser-induced interband self-trapped excitons. The anisotropic structures exhibit birefringent properties, and thus can be employed for multi-dimensional optical data storage applications. Data voxels generated by such short laser irradiation enable on-the-fly high-speed data recording.