In this work, led by our post-doc Tomer, and supported by my numerical simulations, we demonstrated tuning of infrared Mie resonances by varying the carrier concentration in doped semiconductor antennas.
Tomer fabricated spherical silicon and germanium particles of varying sizes and doping concentrations. Single-particle infrared spectra revealed numerous multipolar resonances. We then demonstrated doping-dependent frequency shifts that followed simple Drude models, with plasmonic resonances emerging at high doping levels and long wavelengths.
These findings demonstrate the potential for actively tuning infrared Mie resonances by optically or electrically modulating charge carrier densities, thus providing a starting platform for our subsequent work on electrically-tunable metasurfaces.