ULTRA-FAR-FIELD HIGH-RESOLUTION NANOPATTERNING ON MONOCRYSTALLINE SILICON USING A 3AXICON-LENS OPTICAL SYSTEM

Precise nanopatterning is increasingly critical for advanced micro- and nanofabrication. However, conventional laser-based techniques are often constrained by optical diffraction and require complex, high-numerical-aperture (NA) optics. Laser-induced periodic surface structures (LIPSS) offer an alternative approach, but their intrinsic periodicity and nonuniformity limit the production of uniform, isolated nanoscale features. Here, we report a novel nanopatterning method using a 1030 nm linearly polarized femtosecond laser integrated with a 3Axicon-Lens optical system and galvanometer scanning. This configuration enables ultra-far-field processing (working distance > 85 nm), generating independent, uniform nanopatterns on monocrystalline silicon surfaces. We demonstrate isolated features down to 100 nm, representing the first sub-100 nm patterning on a semiconductor via galvanometer scanning without the use of high-NA objectives or microsphere lenses. These results highlight the enhanced flexibility and scalability of this technique for semiconductor manufacturing, MEMS, and photonics applications.