Enhancing thermal radiation with nanoantennas to create infrared sources with high modulation rates

Abstract : In recent decades, researchers have demonstrated incandescent sources that exhibit monochromatic, directional, and even fast modulated infrared emission. Most of the researchers achieve this type of emission by heating the whole device. Here, we propose heating only nanovolumes that can be cooled in a few tens of nanoseconds. This approach could enable high-speed modulation. To compensate for the weak thermal emission of such isolated nanoemitters, we propose inserting the hot nanovolume in the gap of a cold nanoantenna. We calculate the resulting emission enhancement by using a generalized version of Kirchhoff's law, and demonstrate that careful design of the complete antenna– nanoemitter system can result in emission enhancements of more than four orders of magnitude.