| Autor: |
Eslamisaray MA; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States., Wray PR; Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, United States., Lee Y; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States., Nelson GM; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States., Ilic O; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States., Atwater HA; Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States., Kortshagen UR; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States. |
| Abstrakt: |
Optically Mie-resonant crystalline silicon nanoparticles have long attracted interest for their unique scattering behaviors. Here, we report a bottom-up nonthermal plasma process that produces highly monodisperse particles, with diameters controllable between 60 and 214 nm, by temporarily electrostatically trapping nanoparticles inside a continuous-flow plasma reactor. The particle size is tuned by adjusting the gas residence time in the reactor. By dispersing the nanoparticles in water, optical extinction measurements indicate colloidal solutions of a particle-based metafluid in which particles support both strong magnetic and electric dipole resonances at visible wavelengths. The spectral overlap of the electric and magnetic resonances gives rise to directional Kerker scattering. The extinction measurements show excellent agreement with Mie theory, supporting the idea that the fabrication process enables particles with narrow distributions in size, shape, and composition. This single-step gas-phase process can also produce Mie-resonant nanoparticles of dielectric materials other than silicon and directly deposit them on the desired substrates. |
