Near-Field Mediated 40 nm In-Volume Glass Fabrication by Femtosecond Laser

摘要

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.