Laser-printed hemispherical silicon Mie resonators

Subwavelength nanostructures made of high-index low-loss materials have revolutionized the fields of linear and nonlinear nanophotonics, stimulating growing demands for efficient and inexpensive fabrication technologies. Here, we demonstrate high-precision and reproducible printing of hemispherical Si nanoparticles (NPs) via controllable dewetting of glass-supported a-Si films driven by a single femtosecond laser pulse. The diameter of the formed nanocrystalline NPs can be fully controlled by initial alpha-Si film thickness as well as lateral size of the laser spot and can be predicted by a simple empirical model based on conservation of energy and mass. A resonant optical response associated with Mie-type resonances supported by hemispherical NPs was confirmed by combining numerical modeling with optical microspectroscopy. Inexpensive and high-performing direct laser printing of nanocrystalline Si Mie resonators with a user-defined arrangement opens a pathway for various applications in optical sensing and. nonlinear nanophotonics. (C) 2021 Optical Society of America

Automated summary

The controllable dewetting of glass-supported a-Si films driven by a single femtosecond laser pulse enables high-precision and reproducible printing of hemispherical Si nanoparticles. The diameter of the nanocrystalline NPs can be fully controlled by various factors and predicted using a simple empirical model. The resonant optical response associated with Mie-type resonances supported by the hemispherical NPs was confirmed through numerical modeling and optical microspectroscopy, opening up pathways for various applications in optical sensing and nonlinear nanophotonics.