Department of Electrical and Computer Engineering and ‡Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States.
Nano Lett. 2015 Dec 9;15(12):8188-93. doi: 10.1021/acs.nanolett.5b03679. Epub 2015 Nov 20.
We demonstrate tuning of infrared Mie resonances by varying the carrier concentration in doped semiconductor antennas. We fabricate spherical silicon and germanium particles of varying sizes and doping concentrations. Single-particle infrared spectra reveal electric and magnetic dipole, quadrupole, and hexapole resonances. We subsequently demonstrate doping-dependent frequency shifts that follow simple Drude models, culminating in the emergence of plasmonic resonances 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 an excellent platform for tunable metamaterials.
我们通过改变掺杂半导体天线中的载流子浓度来演示红外 Mie 共振的调谐。我们制造了不同尺寸和掺杂浓度的球形硅和锗颗粒。单颗粒红外光谱揭示了电偶极子、磁偶极子、四极子和六极子共振。随后，我们证明了与掺杂相关的频率位移遵循简单的 Drude 模型，最终在高掺杂水平和长波长下出现等离子体共振。这些发现表明，通过光或电调制载流子密度来主动调谐红外 Mie 共振具有潜力，从而为可调谐超材料提供了极好的平台。
