Spatially controlled nano-structuring of silicon with femtosecond vortex pulses

• Published in: Scientific reports 2020-07, Vol.10 (1), p.12643-12643, Article 12643
• Main Authors: Rahimian, M. G., Jain, A., Larocque, H., Corkum, P. B., Karimi, E., Bhardwaj, V. R.
• Format: Article
• Language: English
• Subjects: 639/624; 639/624/1075/1080; Charged particles; Fabrication; Humanities and Social Sciences; Lasers; multidisciplinary; Photons; Science; Science (multidisciplinary); Silicon
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-69390-4

Engineering material properties is key for development of smart materials and next generation nanodevices. This requires nanoscale spatial precision and control to fabricate structures/defects. Lithographic techniques are widely used for nanostructuring in which a geometric pattern on a mask is transferred to a resist by photons or charged particles and subsequently engraved on the substrate. However, direct mask-less fabrication has only been possible with electron and ion beams. That is because light has an inherent disadvantage; the diffraction limit makes it difficult to interact with matter on dimensions smaller than the wavelength of light. Here we demonstrate spatially controlled formation of nanocones on a silicon surface with a positional precision of 50 nm using femtosecond laser ablation comprising a superposition of optical vector vortex and Gaussian beams. Such control and precision opens new opportunities for nano-printing of materials using techniques such as laser-induced forward transfer and in general broadens the scope of laser processing of materials.