Tomer's recent publication, Widely Tunable Infrared Antennas Using Free Carrier Refraction, was just published in Nano Letters. In this work we fabricate spherical Si and Ge nanoparticles and measure their associated infrared Mie resonances. We show that single nanoparticles can exhibit wavelength shifts arising from continuous doping-dependent tuning of the permittivity between dielectric (epsilon ~ 14) and metallic (epsilon ~ -20) regimes.