Optical antennas are a critical component in nanophotonicsresearch' and have been used to enhance nonlinear2,3andRaman cross-sections and to make nanoscale optical probes5.In addition to their 'receiving' properties, optical antennas canoperate in 'broadcasting' mode, and have been used to modifythe emission rate6 and direction7 of individual molecules.In these applications the antenna must operate at frequenciesgiven by existing light emitters. Using thermal excitation ofoptical antennas, we bypass this limitation and realize emittersat infrared frequencies where sources are less readily available.Specifically, we show that the thermal emission from a singleSiC whisker antenna is attributable to well-defined, size-tunable Mie resonances8. Furthermore, we derive a fundamentallimit on the antenna emittance and argue theoretically that thesestructures are nearly ideal black-body antennas. Combined withadvancing progress in antenna design, these results could leadto optical antenna emitters operating throughout the infraredfrequency range.
展开▼
